A Rationale for Marriage and Its Infidelity Implications

Yoram Barzel (University of washington)
Aurora Stephany (University of Washington)

Abstract: Married women wish to have genetically high fitting children, as well as husbands’ support. There is tension between the two objectives since, as a rule, husbands are not best fitting among accessible males. Wives, then, would gain from affairs with men better fitting than their husbands. We hypothesize that the cause of marriage, and husbands (implicit) commitment to support their wives and children, is husbands’ ability to control their wives to ascertain their fatherhood over the children wives bear. Consistent with the hypothesis, it is observed that in much of history wives have been constrained in such a way so as to reduce their opportunities for affairs even at the cost of lowered productivity. Moreover, wives’ constrains have been extended via social means. By the model here, the (low) level of specialization and limited scale economies within the household, rather than being the cause for marriage as the literature asserts, are the result of husbands’ control, where wives are tied to the homestead. The other explanations for marriage offer no reason for imposing costly restrictions on their wives’ behavior. As husbands’ control is never perfect, however, some wives are still expected to have affairs and bear better fitting children. The gain from affairs is not the same for all wives. Five implications of the disparity and related factors are: 1. The lower is a wife’s standing, the greater her gain from, and thus the greater the expectation of her having an affair. 2. As the ratio of men to women in a society falls, more infidelity is expected. 3. Societies are expected to form norms and enact laws to reduce infidelity. 4. A disproportionate fraction of sport stars and musicians are the children of single mothers. 5. With time, for a given legal environment, the rate of adultery-based divorce should decline. Thus far, however, the implications have not been tested.