What you're describing is polygamy, and I've considered it for myself. It is corrosive if it is adopted as a social institution in a culture, but if a free rider here or there (such as myself) pulls it off, better for them. I have talked to my wife about it, she doesn't like the idea, although she does like women and it wouldn't be a just me getting the benefit type deal. I think she's probably right, the dynamic can get too messy, and I think youre right, it took me my whole life to find her, finding another one that's perfect for me as well as perfect for her would probably take a decade. Not really a reasonable timeline.
Also, she wants the children she raises to be hers, the shared responsibility thing doesn't appeal to her, and the potential rivalries between women and their respective children just aren't conducive to raising healthy people, which is ultimately the goal of all of this. Maybe she will change her mind one day. Maybe it could be made to work. I'm not dead set on it and am happy with the status quo.
Also, she wants the children she raises to be hers, the shared responsibility thing doesn't appeal to her, and the potential rivalries between women and their respective children just aren't conducive to raising healthy people, which is ultimately the goal of all of this. Maybe she will change her mind one day. Maybe it could be made to work. I'm not dead set on it and am happy with the status quo.