Jealousy has for so long been seen as a totally negative emotion that I believe it is time to redress the balance. Because scientists have focused primarily on the obvious reproductive benefits of men's desire for sexual variety, the potential benefits to women of short-term sexual passion languished for years unstudied. In fact, historically, women may have benefited from an affair in countless ways. The most obvious benefit comes from the direct resources that another partner may provide. A few expensive dinners may not seem like much today but an extra supply of meat from the hunt would have made the difference between starving and surviving during ancestral winters, or between merely surviving and robustly thriving during more plentiful times.
Women can also benefit from affairs in the currency of quality genes.
Research reveals that women may be choosing affair partners with especially healthy genes. During ancestral times, disease, warfare and food shortages made survival a precarious proposition. The odds were not trivial that a husband would succumb to a disease, become debilitated by a parasite, or incur injury during a risky hunt or tribal battle. A woman's husband, in short, stood a significant chance of suffering some severe injury or lethal wound. Modern women have simply inherited the desires of their ancestral mothers.