I'm going to be completely honest here, as I've reflected a LOT on why I so desperately wanted a man in my 20s and why - in my 40s and recently separated - I couldn't care less about having a man in my life.
In 2004, when I was 24 and a young professional living in rented accommodation I really began to feel a primal urge to have children.
An almost equally strong urge I had was to own my own home, after years of horrible renting experiences (some quite traumatic, being burgled by my landlady's relative, being SA by my landlord).
So when my H came along and offered me both housing security and the potential for children I jumped at the chance to marry him, which I did.
Then the marriage fell apart when the kids were teens. I'm 44 now.
I own my house outright. My two teen DDs are amazing and all the live in company I need.
Perimenopause (and multiple experiences of SA) have seen to my sex drive.
I don't feel any kind of primal or survival need to have a man in my life. Even if I did, the risks are too high - potential for them to abusive to my DD's or me just why would I bother for so little return?
I would say that in my line of work I work with a LOT Of kids and it's always Dad who moves in. Usually with a single mother with her own home.
I often think it's as much to do with financial stability - if the woman keeps the home (because she keeps the kids) then it makes sense for the man to move in with a woman with her home (see this across all social strata - whether she's a homeowner or has her own social housing).
I think it has far less to do with emotions (on either side) than it does with practicialities. We just don't like to admit that.