Individuals differ, of course, in the strength of this desire—the distributions overlap, and some women exceed some men, just as they do in weight or height. Individuals also differ in whether this desire is expressed in actual mating behavior, such as casual sex, affairs, or patronizing prostitutes. Many men choose not to act on their desires. Some lead lives of quiet desperation. They suffer longings unfulfilled due to moral, religious, or reputational considerations, or simply because they lack opportunity. “A man is only as faithful as his options,” according to comedian Chris Rock.

