No group-living nonhuman primate is monogamous, and adultery has been documented in every human culture studied- including those in which fornicators are routinely stoned to death. In light of all of this bloody retribution, it's hard to see how monogamy comes "naturally" to our species. Why would so many risk their reputations, families, careers- even presidential legacies- for something that runs against human nature? Were monogamy an ancient, evolved trait characteristic of our species, as the standard narrative insists, these ubiquitous transgressions would be infrequent and such horrible enforcement unnecessary. No creature needs to be threatened with death to act in accord with its own nature.
Christopher  Ryan, Sex at Dawn: The Prehistoric Origins of Modern Sexuality
human-nature, monogamy, sexuality