As far as kids go. It’s definitely a personal choice that has to be right for the person. I’ve met many who don’t have kids either by choice or by nature and they are perfectly happy in their lives. I’ve met plenty of happy people with kids, but also unhappy people. For me, having my daughters has been a paradigm shifting life changer. My happiness and pleasure is now tied to them. When I was single and without children, I would pursue my individual pleasure particularly in the “dating” world above most other pleasures, but now nature has put me in charge of these little ones. I’m only as “happy” as my saddest kid. So I’m tied to them.
Co-parenting and “romance” are pretty far apart on the Venn diagram in general. They can join up, but in general the roles change entirely once the wee ones appear.