historically is hard to say, most of the time effectively most relationships were monogamous, but cuckoldry sometimes threw a wrench in it, then there were cultures that were polygamous by policy but given one woman was usually all someone could afford meant that monogamy usually ruled. in highly rural areas, contact with others was sparse anyway so women would usually have to be with someone in the area lest they risk a long journey. if there were too many women this could lead to polygamy by necessity, if there were too many men they would risk the journey instead, but the difference is they would actually do it, balancing out the area. when monogamy got the official endorsement of a government or religion it usually only affected the ruling classes. but all i know for sure is that i wanted monogamy my whole life and no women wants to be in a relationship with me. they still only want to be shared by the same "high" men, every and any fantasy they have "dangerous", "huge", "intimidating", "sexually powerful" pops into their head and with the likes of tinder they can go shopping for it, and resources are usually enough to go around, and places for all their social fracture and architectural placelessness are easily tied together by a littany of roadways that for all their faults offer a near unparalleled ability to access people and places far away safely, so it seems clear that to some degree we have passed into a post scarcity society due to high industrialization and taking advantage of 2nd world economies so that our women can flirt with the idea that any man they find sexually appeasing will be a suitable mate, and thus they don't feel the need to feign interest in monogamy anymore. tl;dr if a woman can be a whore she will be a whore
United States