Parenting issues

Why would your baby momma or baby daddy want to be friends after y’all establish you can’t be together ? For one shouldn’t the convos be bout your child not so much what the other person got going on ? I have issues with this completely. My bd moved on and I really don’t care but why is he asking me what I got going on or if I got plans ? I’m the only one that talks bout our daughter I don’t really say much else on anything else. I just ask how he doing bout it. But why does he go out of his way to have meaningless convos like asking me if I’m going to move out or anything what’s that got to do with anything. He might try to be nice and go bout things but still. He didn’t care bout bringing up his past relationships with his bm but he doesn’t mention the new relationship that he supposedly has. I don’t get it at all ?! Someone please explain this. I’m trying to be civil not argue but lately he’s been having some smart ass remarks lately. I don’t understand what he’s so angry bout with me ?! I really didn’t choose to be his friend cause I didn’t think it was the right thing to do.

I dont know either

My partner doesn't talk to her apart from what time Sundays to pick his son up. He knows nothing else and tbh. I wouldn't have accepted him as a romantic partner if he did. So I don't think that is right and you know how these estranged parents some times boomerang between each other, wasting others lives in the process