All of them. They couldn't establish themselves enough to leave any important traces in history and are effectively erased. Sexual liberation is not a new idea, the reason why it's not traditional is because it is unsustainable and can never grow to a tradition
You do realize people can have sex, procreate and raise families without marriage, right? "Sexual liberation" doesn't negate sex, it only negates the proscription of involuntary sex and gender roles through patriarchy.
Also:
>All of them.
All of whom? Surely you can give us specific examples. Your certainty must based on solid archaeological and anthropological evidence, right?
This is a... hard anthropological claim to make. I don't claim to be an expert anthropologist, but I would note that marriage means very many things to different peoples. 'Western' marriage, as it were, is already fraught. One man and a women, sharing property? Well, what about two men, two women, or other genders? Non-cishetnormative understandings complicate this picture quite quickly. And what of property? The capitalist idea of property isn't the only one, and different understandings of property will, historically speaking, lead to different understandings of marriage.
All of this is to say that marriage is a fraught societal construct, not a societal neccessity.
This thread took a bit of a wild turn, but I felt I had to respond :)