To achieve a successful marital partnership is probably the most difficult of life's social requirements, whether successful is defined biologically as the production of healthy offspring or in the more human terms as achieving a relationship which allows each partner to lead a satisfying life. To be successful each marital partner must often defer to the other, especially if there are dependent children present. Failure to show this capacity to defer or to be unselfish inevitably leads to conflict, and conflict can easily build up to the point of violence. The ethological study of animal reproduction, including that of primates, shows how universally true this is and what a wealth of convention and ritual is developed to reduce such dangerous confrontation.