To be fair monogamous marriage is no bastion of female liberation. Historically it has been used as a form of control, isolation and confinement of women. All over the world.
And yet a harem can be even worse than that! Talk about a low bar... Non monogamous (for both partners) and non blood related family is better. Every movie in Hollywood is about choosing your family. It's because families can suck! And marriages can suck too! You need to be able to choose your own extended family. At the same time that family cannot turn into a chain, a prison, it is telling both are common metaphors for marriage.
And we have all types of weird hang-ups about sex. Have sex with anyone you want. Don't fall for the incel/cuck propaganda. Raise other people's children as if your own, every divorcee and widow goes through that, it is normal. Every piece of media your whole life talks about how love trumps all, idk how people ended up at cucks instead.