Objectives: To investigate what kind of changes spouse caregivers of demented patients experience after the onset of dementia (a) in the general atmosphere, happiness, and relations of marriage and (b) in the sexual side of marriage. Design: Semistructured telephone interviews of spouse caregivers of demented patients. Setting: Community-living demented patients and their spouse caregivers in eastern Finland. Participants: The spouse caregivers of 42 demented patients recruited from a previous intervention study. Measures: The questionnaire covered different areas of marriage from the time before and after the onset of dementia. Results: A statistically significant decline had occured in extent of happiness (p = .012), in equal relations (p = .001), and in patients' expressions of sexual needs (p < .001) when compared the time before and after dementia. Twenty-five (60%) of the caregivers reported that the demented patient had shown at least one negative sexual behavioral change during the course of dementia. Seven male patients (24%) had shown the behavioral symptom of constantly expressing need for making love. One in 10 caregivers had experienced positive sexual behavioral changes. In one third of the patients, the expressions of tenderness towards the caregiver had increased. Dementia did not affect significantly the general atmosphere of the marriage. Out of those still in home care, at 3 years from the onset of dementia, 19 couples (46%) continued to practice intercourse, at 5 years the number was 15 couples (41%), and at 7 years it had declined to 7 couples (28%). Conclusions: Dementing illness has a major negative impact on many dimensions of marriage. However, there are also positive changes and preserved aspects of marriage. Dementia seems to have a surprisingly little impact on whether the couple continues to have intercourse when compared with the general aging population.