
Back in the cavemen area women were largely “whores” as the idea of bloodline being passed on was not a thing. Women were also hunters just like men. Once people had excess food, roles became more specialized and women naturally became caregivers as they were more biologically suited to that.
From there, villages became a thing and originally it didn’t matter who’s kid it was the whole village helped raise it. I think it was like around the Victorian era that the idea of bloodline being passed down became important, thus the idea that women should not sleep with multiple men as then they wouldn’t know who’s kid it was.