After choosing a mate, females bear the brunt of child production. Not only does the woman have to produce and carry the baby, in a majority of cultures she remains responsible for raising him or her. Because offspring are at such a high cost for the female, the male’s resource contribution could mean life or death for her and her child, weighing significantly on her fitness potential (Schutzwohl, 2008, 93). If a woman knows or suspects that her husband is being unfaithful, she will be more concerned that he is sharing his resources with another female, rather than making another baby (Schutzwohl, 2008, 93). As a result, for females, emotional infidelity is significantly more vexing than sexual infidelity. In a study done to determine the behavioral differences between men and women in terms of jealousy, researchers found that women were most upset when they found out, or suspected that their mate had given a gift to another woman, closely followed by spending time with another woman, and spending time thinking about another woman (de Weerth, 1993, 271). These are considered the worst offenses because the man is giving away both the monetary resources, and the time that he could be using to support his child. By giving a gift to another woman, the man may not directly take much away from the fitness of his primary mate, but he perpetuates a threat that he may shift all of his resources to another woman, which would be dramatically detrimental to the fitness of his primary mate, as well as her child. In the same study, women also self-reported more overall jealousy in relationships than men did. This is likely due to the parental investment costs that females incur – females have more to lose with an unfaithful spouse (de Weerth, 1993, 266-268).
