I know I'll be ok but it still hurts

I know I've been alot of things in my past and I know I wasnt the best girlfriend sometimes but youd think he'd be a little more understanding towards his pregnant ex girlfriend. This is his child after all. His baby momma asked him to sign over his parental rights when he got with me and she found out he was having a baby. She's always trying to keep his kids from him but hes always there fighting for his children. He'll do ANYTHING she asks him for. Any small argument we have turns into a major one with him always leaving or I kick him out. He says I want him to abandon his kids (which I dont) and I'm the worst thing that happened to him. I nag because I want to spend time together and hes never here for me or my pregnancy. I've endured everything by myself. All he does is try giving me money like a charity case. It hurts, because he was never like this before I got pregnant. It just sucks cus my baby wont grow up with a father. I'm strong enough to keep it together for her. But I'm pregnant and all this shit just hurts even more. I wish I had chosen better. Regardless of how I've been in the past I dont deserve this constant shit, specially during pregnancy.