1. Dyson Holdings v Fox[1975] 2 All ER 1030 at 1035–1036.

2. See Probert, R ‘“Family law”: a modern concept’ (2004) 34 Family Law 901 Google Scholar.

3. Cf. Fitzpatrick v Sterling Housing Association[2001] 1 FCR 21, where a same-sex couple was held to constitute a ‘family’ for the purposes of tenancy succession under the Rent Act 1977. See also Re R (a child)[2003] EWCA Civ 182, where Art 8 of the ECHR (‘respect for family life’) was invoked to hold that genetic fatherhood may not always produce family life, but social fatherhood might.

4. Probert, above n 2, at 904. Cf. Douglas, G An Introduction to Family Law (Oxford: Oxford University Press, 2001) p 2 Google Scholar: ‘[T]he family is not a naturally occurring fixed phenomenon but a concept which is constructed in a multiplicity of ways and for a variety of purposes.’

5. See, eg, Barlow, A, Duncan, S, James, G and Park, A ‘Just a piece of paper? Marriage and cohabitation in Britain’ in Park, A et al (eds)British Social Attitudes: The 18th Report – Public Policy, Social Ties (London: Sage, 2001 Google Scholar).

6. These whether the partners are of the same or different gender.

7. See Hansard HL, vol 630, col 1692, 25 January 2002 (Lord Lester of Herne Hill).

8. Note that in this paper I will largely disregard provisions for relief regarding children, notably in Sch 1 of the Children Act 1989, since they are not specific to any particular form of domestic relationship. The discussion here is concerned with relationship-specific factors in relief awards.

9. Law Commission Cohabitation: The Financial Consequences of Relationship Breakdown (London: HMSO, 2007), following LCCP 179 (London: HMSO, 2006). Cf. Law Commission Sharing Homes: A Discussion Paper (London: HMSO, 2002).

10. See Cretney, S Same Sex Relationships: From ‘Odious Crime’ to ‘Gay Marriage’ (Oxford: Oxford University Press, 2006) p 39 CrossRefGoogle Scholar: ‘As he said unmarried heterosexual couples – just like the much smaller number of same sex couples – are treated “much less favourably than married couples, even if they have close and long-standing relationships…. In several ways their legal position is either inferior or not recognised as a family status at all”.’

11. Lord Hardwicke's Act ‘for the Better Preventing of Clandestine Marriages’. Regarding the regime supplanted by the Act, see Probert, R Marriage Law and Practice in the Long Eighteenth Century: A Reassessment (Cambridge: Cambridge University Press, 2009 CrossRefGoogle Scholar).

12. In 1971 the Nullity of Marriage Act explicitly banned marriages between same-sex couples in England and Wales, a restriction preserved in the Matrimonial Causes Act 1973. In Scotland, the Marriage (Scotland) Act 1977 validates marriage only between heterosexual partners, as does the Marriage (Northern Ireland) Order 2003.

13. Cf. the historical doctrine of couverture: Pollock, F and Maitland, Fw The History of English Law (Cambridge: Cambridge University Press, vol II, 1968) p 432 Google Scholar.

14. Hansard HC, vol 425, col 174, 12 October 2004. Notably, this parallel extends to excluding partnerships with close relatives: CPA 2004, s 3(1)(d) and Sch 1, Pt 1.

15. Cf. the proceedings of the House of Commons Standing Committee D.

16. Indeed, the disanalogy is also a source of resentment. For some same-sex couples, the ‘parallel but different’ public commitment of a civil partnership is not enough. They see marriage as the ‘gold standard in social respectability and recognition of relationships’, and feel that they have been given an inferior social institution in the form of civil partnerships. See, eg, Bailey, M ‘Regulation of cohabitation and marriage in Canada’ (2004) 26 Law and Policy 153 CrossRefGoogle Scholar at 154 n 8.

17. Cf. Lord Filkin (Minister of State in the Department of Constitutional Affairs) Hansard HL, vol 657, cols 1094–1095, 11 February 2004, emphasising the difference between civil partnership and marriage. Note that English law has since been modified by s 198 of the Equality Act 2010, which abolishes the husband's common law duty of support. Other distinctions, including criminal law duties, may well remain in the common law. Cf. Plummer (1844) 1 C & K 600, 174 ER 954; Russell[1933] VLR 59; Horder, J and McGowan, L ‘Manslaughter by causing another's suicide’ (2006)Crim LR 1035 Google Scholar at 1044, citing Hood[2003] EWCA Crim 2772, [2004] 1 Cr App R (S) 73.

18. Cf. Cretney, above n 10, p 35.

19. See CPA 2004, s 44(4); Matrimonial Causes Act 1973, s 1(4). See also Cretney, ibid, p 33, who notes that ‘adultery’ (which is limited to heterosexual intercourse) could have been given a parallel definition for the purposes of the CPA 2004.

20. CPA 2004, s 1(1)(a).

21. Ibid, s 2(1).

22. Ibid, s 2(3).

23. Glennon, L ‘Obligations between adult partners: moving from form to function’ (2008) 22 Int J Law, Policy and the Family 22 CrossRefGoogle Scholar at 26: ‘The “relational equality” agenda of civil partnerships is premised on notions of formal equality and the symbolic view of partnership recognition regardless of whether the characteristics of individual relationships within the legal category require the bundle of rights and duties which accompany the newly constituted status of civil partnership.’ For cohabitants, too, the celebration of marriage as a social event appears to be one of its most appealing aspects, with the institutional and religious elements its most unappealing features. See Barlow, A, Duncan, S, James, G and Park, A Cohabitation, Marriage and the Law (Oxford: Hart, 2005) p 69 Google Scholar: ‘The major reason for wanting marriage, either as a vague expectation or as a practical plan, was for public performance and display.’

24. For an interesting comparison of traditions, see Tan, C ‘ “We are registered”: actual processes and the law of marriage in Singapore’ (1999) 13 Int J Law, Policy and the Family 1 CrossRefGoogle Scholar.

25. Barlow, A, Burgoyne, C, Clery, E and Smithson, J,‘Cohabitation and the law: myths, money and the media’ in Park, A et al (eds)British Social Attitudes: The 24th Report (London: Sage, 2008) p 30 Google Scholar.

26. Stack v Dowden[2007] UKHL 17, eg, at [56].

27. Ibid. Where these is such an intention, but no agreement about the quantum of the parties' respective shares, it seems that courts can now impute a distributive criterion of fairness: Jones v Kernott[2011] UKSC 53; although this possibility remains subordinate to the parties' actual intentions.

28. Cf. Lloyd's Bank v Rosset[1991] 1 AC 107.

29. For example, Pascoe v Turner[1979] 2 All ER 945 (CA).

30. See, eg, Amin & Amin v Amin & Ors[2009] EWHC 3356 (Ch) (brothers).

31. A misapprehension attributable to roughly half the United Kingdom population: Barlow et al, above n 25, pp 40–42.

32. Burns v Burns[1984] Ch 317 (CA).

33. Douglas, G, Pearce, J and Woodward, H A Failure of Trust: Resolving Property Disputes on Cohabitation Breakdown (Cardiff: Cardiff Law School, 2007 Google Scholar) chs 4 and 5.

34. Barlow et al, above n 25, pp 44ff.

35. Law Commission, above n 9.

36. Neither did the subsequent Cohabitation Bill (introduced unsuccessfully as a private member's bill by Lord Lester in December 2008), which primarily sought to give protection according to need.

37. Maclean, M and Eekelaar, J ‘Marriage and the moral bases of personal relationships’ (2004) 31 J Law and Society 510 Google Scholar at 538.

38. Barlow, above n 25, p 40; also see pp 35 and 47.

39. Gardner, S and Davidson, K ‘the future of Stack v Dowden’ (2011) 127 LQR 13 Google Scholar at 17–19. See, eg, at 17: ‘Where their relationship is materially communal, [the argument] is that the outcome does, and reasonably might, reflect the apparent implication of this, that the property should belong to them equally.’

40. And, worse, that the titles are possessive and carry uncomfortable historical connotations.

41. Home Office, Supporting Families: A Consultation Document (London: HMSO, 1998) s 4.8. Recent Home Office policy has been more equivocal.

42. Cf. Kiernan, K ‘Unmarried cohabitation and parenthood in Britain and Europe’ (2004) 26 Law and Policy 33 CrossRefGoogle Scholar at 53.

43. Goodman, A and Greaves, E Cohabitation, Marriage and Child Outcomes (London: Institute of Fiscal Studies, 2010 Google Scholar).

44. For example, funding community-based organisations that promote parenting schools, or, perhaps even more importantly, resourcing educational incentives for young persons from poor backgrounds since educational attainment typically affects employability and other life prospects.

45. Cf. Sch 1 of the Children Act 1989. See also the Child Support Act 1991 and its successors.

46. Hansard HL, vol 730, cols 117–120, 6 September 2011.

47. A striking example is Dewar, J ‘the normal chaos of family law’ (1998) 61 MLR 467 CrossRefGoogle Scholar.

48. Glennon, above n 23.

49. Hence it is intelligible to conclude that one who has an affair with a married person wrongs, extra-legally, that person's spouse; something for which English law allows in its criteria of divorce.

50. A helpful discussion of this idea is Lamond, G ‘Coercion, threats and the puzzle of blackmail’ in Simester, Ap and Smith, Ath (eds)Harm and Culpability (Oxford: Oxford University Press, 1996) p 233 Google Scholar. For one rather obvious example, now adultery becomes a wrong not just against the world (if it ever were), but against one's spouse in particular. It is a breach of promise, a betrayal.

51. For illuminating discussion, see Fitzgibbon, S ‘Marriage and the good of obligation’ (2002) 47 American J Jurisprudence 41 CrossRefGoogle Scholar.

52. This includes adopting the ad hoc approach proposed by Gardner and Davidson (above n 39, at 19), whereby we apply a matrimonial ‘treatment to those relationships which merit it’.

53. In a move driven by economic considerations, the social security system has taken some steps down this path already: treating heterosexual cohabitants (since 1966) and same-sex cohabitants (since 2005) as if married or civilly partnered for the purposes of benefit allocations.

54. It is not, in particular, the ‘freedom’-based argument made by Deech, R ‘The case against legal recognition of cohabitation’ in Eekelaar, J and Katz, N (eds)Marriage and Cohabitation in Contemporary Societies: Areas of Legal, Social and Ethical Change (Toronto: Butterworths, 1980) p 300 Google Scholar. Deech argues for a highly individualistic approach to post-breakdown remedies, emphasising the separateness of the participants. But as she herself sees, her argument applies to marriages too (p 303): ‘Cohabitation could only be assimilated to marriage if the legal incidents of marriage itself were reduced (which would be no bad thing)…. In other words, marriage should become more like cohabitation and not the other way around.’ My argument is not for assimilation but for differentiation.

55. Raz, J The Morality of Freedom (Oxford: Oxford University Press, 1986 Google Scholar).

56. Admittedly, the force of the objection on religious grounds has been ameliorated, albeit incompletely, by the enactment of civil wedding provisions.

57. Cf. Barlow et al, above n 25. For discussion of the term ‘common law’ in this context, see Probert, R ‘Common law marriage: myths and misunderstandings’ (2008) 20 CFLQ 1 Google Scholar.

58. Including money management decisions within the partnership: Vogler, C, ‘Managing money in intimate relationships’ in Miles, J and Probert, R (eds)Sharing Lives, Dividing Assets: An Inter-disciplinary Study (Oxford: Hart, 2009) p 61 Google Scholar.

59. Barlow et al, above n 25, p 32–33.

60. Not everyone thinks so. See, eg, Auchmuty, R ‘Out of the shadows: feminist silence and liberal law’ in Munro, V and Stychin, C (eds)Sexuality and the Law: Feminist Engagements (Abingdon: Routledge-Cavendish, 2007) p 91 Google Scholar. Auchmuty rightly worries about the risks of rushing into a civil partnership when the partners are ignorant of its legal implications. Certainly, entering into a civil partnership is not always the right choice, but that does not seem a good reason to remove the possibility altogether.

61. See, eg, H Ross, K Gask and A Berrington ‘Civil partnerships five years on’ in C. Smith (ed) Population Trends No. 145 (London: Office of National Statistics, 2011) pp 172 and 183ff.

62. Matrimonial Causes Act 1973, s 25(2)(f).

63. See CPA 2004, s 72(1).

64. Thornton, M Public and Private: Feminist Legal Debates (Melbourne: Oxford University Press, 1995 Google Scholar). Cf. Sir Henry Sumner Maine Ancient Law: Its Connections with the Early History of Society and Its Relation to Modern Ideas (London: John Murray, 1861, 10th edn 1912) p 134.

65. Thornton, ibid, p 10.

66. Waring, M Counting for Nothing: What Men Value and What Women are Worth (London: Allen & Unwin, 1988 CrossRefGoogle Scholar).

67. Paull, G ‘the impact of children on women's paid work’ (2006) 27 Fiscal Studies 473 CrossRefGoogle Scholar. Average women's wages gradually decline for about ten years after the first birth, and stagnate for a further ten years before making a slight recovery.

68. Paull reports (ibid) that prior to childbirth, men and women are equally likely to participate in paid employment. After the arrival of children, the percentage of men participating in the labour market rises from 82 to 88 per cent, while levels of employment fall from 83 to 62 per cent for mothers. The gap narrows between the sexes once children have left home, but never completely disappears again (84 per cent for men and 73 per cent for women).

69. This point is well documented in the tax-benefit literature (eg, Pahl, J ‘personal taxation, social security and financial arrangements within marriage’ (1986) 13 J Law and Society 241 CrossRefGoogle Scholar at 242–246) and receiving increasing attention in socio-legal contexts. See, eg, Vogler, C, Lyonette, C and Wiggins, Rd ‘Money, power and spending decisions in intimate relationships’ (2008) 56 Sociological Review 117 CrossRefGoogle Scholar.

70. Cf. Bottomley, A ‘Self and subjectivities: languages of claim in property law’ (1993) 20 J Law and Society 56 CrossRefGoogle Scholar at 62, arguing that the requirement of a specific promise of ownership rather than use in case-law ‘is not only a requirement of a certain jurisprudential approach but also a mode of reasoning and language that is more conducive to men than women’.

71. [1970] AC 777.

72. [1971] AC 886. These judgments rejected the more generous ‘family assets’ interpretation of s 17 of the Matrimonial Causes Act 1882 found in Fribance v Fribance (1957) 1 WLR 384 where, at 387, Lord Denning LJ pronounced that ‘the whole of [the spouses] resources were expended for their joint benefit – either in food and clothes and living expenses for which there was nothing to see or in the house and furniture which are family assets – and the product should belong to them jointly. It belongs to them in equal shares.’

73. Matrimonial Proceedings and Property Act 1970. See the Matrimonial Causes Act 1973, s 25.

74. White v White (2001) 2 FLR 981.

75. Ibid, at 989.

76. [2006] UKHL 24, [2006] 2 AC 618 (hereafter Miller/McFarlane) at [138].

77. Ibid: an approach developed in the 1970s in accordance with s 25(2)(b) of the Matrimonial Causes Act 1973. See also Cooke, E ‘Miller/McFarlane: law in search of discrimination’ (2007) 19 CFLQ 98 Google Scholar at 99–100.

78. I leave aside here the further question of to what extent such things as inheritances or other separate funds should count as family assets or ‘matrimonial property’. See, eg, K v L (Ancillary relief; inherited wealth)[2011] EWCA Civ 550. That difficult issue is not central to the discussion here. It seems clear, however, that the existence of non-matrimonial property does not override the basic principle of equal sharing. Cf. Jones v Jones[2011] EWCA Civ 41, [2011] 1 FCA 242.

79. [2007] EWCA Civ 503, [2007] 1 FLR 1246, esp [65] and [76](b).

80. Miller/McFarlane, above n 76, at [4].

81. A point made by commentators: eg, Cooke, above n 77.

82. Miller/McFarlane, above n 76. Although not developed in the judgment, the Court in Charman v Charman (No 4)[2007] EWCA Civ 503 at [69]–[72] also comments on its presence within existing case-law, and the accommodating operation of the statutory checklist in s 25 of the Matrimonial Proceedings Act 1973.

83. See Miles, J ‘Charman v Charman (No 4): making sense of need, compensation and equal sharing after Miller/McFarlane’ (2008)CFLQ 378 Google Scholar at 390.

84. See Miller/McFarlane, above n 76, at [15] (Lord Nicholls) and [140] (Baroness Hale).

85. Miles, above n 83, at 391.

86. See, eg, Hochschild, A and Machung, A The Second Shift: Working Parents and the Revolution at Home (New York: Viking Penguin, 1989 Google Scholar); Seccombe, W ‘Domestic labour and the working class household’ in Fox, B (ed)Hidden in the Household (Toronto: Women's Educational Press, 1980 Google Scholar); Eichler, M Families in Canada Today: Recent Changes and Their Policy Consequences (Toronto: Gage, 2nd edn, 1988 Google Scholar).

87. According to the Central Statistical Office Social Focus on Women (London: HMSO, 1995), if separation occurs, nearly half of women see their income drop compared to only a fifth of men's. Or, in average terms, the income of men increases by 23 per cent upon divorce, while that of women falls by 31 per cent. H Fisher and H Low ‘Who wins, who loses and who recovers from divorce’ in Miles and Probert, above n 58, p 227.

88. The motivation is important. Compare Radmacher v Granatino[2010] UKSC 42 at [121]: ‘There is no compensation factor in this case. The husband's decision to abandon his lucrative career in the city for the fields of academia was not motivated by the demands of his family, but reflected his own preference.’ Baroness Hale's more sympathetic analysis is also predicated on motive (at [194]).

89. Duncan, A, Giles, C and Webb, S The Impact of Subsidising Childcare (London: Equal Opportunities Commission, 1995) pp 5–6 Google Scholar. More recently, see also the analysis by J Scott and S Dex ‘Paid and unpaid work: can policy improve gender inequalities’ in Miles and Probert, above n 58, p 41.

90. See, eg, Anderson, T, Forth, J, Metcalf, H and Kirby, S The Gender Pay Gap: Final Report to the Women and Equality Unit (London: Cabinet Office, 2007 Google Scholar); Waldfogel, J ‘the price of motherhood: family status and women's pay in a young British cohort’ (1995) 47 Oxford Economic Papers 580 CrossRefGoogle Scholar.

91. Cf. Waring, M. If Women Counted: A New Feminist Economics (San Francisco, CA: HarperCollins, 1990 Google Scholar). Interestingly, it seems that married women do more unpaid work than cohabiting women in similar circumstances. See South, S and Spitz, G ‘Housework in marital and nonmarital households’ (1994) 59 American Sociological Review 327 CrossRefGoogle Scholar.

92. Bianchi, S, Robinson, J and Milkie, M Changing Rhythms of American Family Life (New York: Russell Sage, 2006 Google Scholar).

93. Hakim, C ‘Erotic Capital’ (2010) 26 European Sociological Review 499 CrossRefGoogle Scholar.

94. [2011] EWCA Civ 41 at [35] (Wilson LJ); see also [64] (Arden LJ).

95. See, eg, the studies in Dunne, G Living Difference: Lesbian Perspectives on Work and Family Life (Binghamton, NY: Haworth Press, 1998 Google Scholar).

96. Cf. Auchmuty, R ‘When equality is not equity: homosexual inclusion in undue influence law’ (2003) 11 Feminist Legal Studies 163 CrossRefGoogle Scholar; although see her later worries in Auchmuty, above n 60, pp 114–116.

97. Above n 76.

98. Cf. ibid at [16]; Charman v Charman (No 4)[2007] EWHC Civ 503 at [65].

99. Even so, if a governing principle of compensation should ever be adopted for cohabiting relationship breakdowns, the argument in this section would have application in that context (subject to the first two limitations identified above).

100. Bianchi et al, above n 92, p 392.

101. See now Radmacher v Granatino[2010] UKSC 42. The Supreme Court's decision to give weight to pre- and post-nuptial contracts, varying the prima facie terms of a package deal, is compatible more generally with the arguments being made here since it reflects the greater autonomy of many women entering modern marriages. Such a development would certainly have been inappropriate in the traditional world described by Baroness Hale (at [139]).

102. Cf. s 12(a) of the Matrimonial Causes Act 1973: a marriage is voidable if either party is incapable of the act of consummation.

103. Cf. Sutton v Mischon de Reya and Gawor and Co[2004] EWHC 3166. The contract over property division upon relationship breakdown cannot apply if sexual services constitute part of the consideration. On limiting rights and responsibilities, see Glennon, above n 23.

104. An illustrative variety of definitions is collected in Cole, C. ‘Cohabitation in social context’ in Libby, R and Whitehurst, R (eds)Marriage and Alternatives: Exploring Intimate Relationships (Glenview, IL: Scott Foresman, 1977) p 62 Google Scholar.

105. Radmacher v Granatino[2010] UKSC 42 at [73]–[85]: it is subject to overriding considerations of fairness, most notably according to the principles of need and compensation (at [81]).

106. This is consistent with the conclusion in Radmacher v Granatino, ibid, at [53]–[61], where the majority rejected a distinction between pre- and post-nuptial agreements. Their Lordships' analysis presupposes that the relationship is ongoing, which supports distinguishing the kinds of agreement on a different basis – between ‘nuptial’ and separation agreements (cf. [65]).

107. On the difficulty of assessing the economic costs of career sacrifice, see Miles, above n 83, at 393, citing Coleridge J in RP v RP[2006] EWHC 3409 (Fam), (2007) 1 FLR 2105 at [59]–[64], endorsed by the President in VB v JP[2008] EWHC 112 (Fam), (2008)1 FLR 742 at [52]. Contrast Eekelaar's preferred approach to compensation: ‘Property and financial settlements on divorce: sharing and compensating’ (2006) 36 Fam Law 754.

108. Office for National Statistics, Statistical Bulletin: Civil Partnerships in the UK (London: Office for National Statistics, 19 August 2010): from 180 in 2008 to 351 in 2009.