Marital infidelity

Among American couples, adultery prevalence estimates range from at least one fifth of husbands and one tenth of wives to as high as 72% of husbands and 54% of wives, depending on the survey.

“Given this unharmonious set of factors, it can hardly come as a surprise that at least one fifth of husbands and at least one tenth of wives commit adultery. These numbers—for American couples—range as high as 72 and 54 % respectively, depending on the survey (see Greeley 1994; Allen et al. 2005).”

Ease of long distance travel and the ballooning size of social groups increase opportunities for comparatively low-risk love affairs.

“Ease of long distance travel and the ballooning size of social groups increase opportunities for such (comparatively) low-risk love affairs (Greeley 1994).”

Natural selection did not shape basic mating strategies nor underlying brain chemistry to foster life-long, monogamous matrimony in the modern world, but rather to promote reproductive success of progenitors in the Pleistocene.

“Natural selection did not shape our basic mating strategies—nor our underlying brain chemistry—to foster life-long, monogamous matrimony in the modern world, but rather to promote the reproductive success of our progenitors in the environment of the Pleistocene [2, 3].”