I’ve often wondered if it arose, at least in part, as a means of combatting a sexually transmitted disease. But I don’t know if that makes any sense as it would require both knowledge of the disease process and how it is spread.

Still, it is one strong idea of why women would accept sexual monogamy even with culture attempting to force the issue. Women have more open reproductive systems and so are more likely to catch an STD. If you noticed that any woman who slept with Drippy Willy subsequently got sick and maybe died or couldn’t have children anymore … it’s not hard to imagine a willing and sharp curtailing of sleeping around.

After that, maybe it just became a cultural norm that was then exploited over time to male advantage.