What should i do about my ex (he's my baby's daddy)

You can't FORCE somebody to be a Dad. The only thing that you can force him to do is pay child support. He doesn't have to see his child if he doesn't want to. Sad but true.

This is a hard question to answer because there aren't any details. As for my opinion, a man throwing a pregnant woman out obviously wasn't thinking of your child at the time and sometimes kids going back and forth between parents can be just as hard as missing one depending on how well their parents get along. Not to mention that if you both move on it adds to the complexity of the situation. That's just answering from my experience with my kids.

He kicked you out while pregnant. What else does he have to do--physically hit you or the baby? Give up your fairy tale of him being a good dad. Get away, work on you so you don't hook up with another loser---and make a better life for you and your child. You can't heal your past by letting someone abuse you in the present. YOU can't change the past by being a doormat now. You need the help and direction to deal with and heal from the lack of a father in your life--BUT you will not be able to replace that with him. He isn't a man, he is an immature boy---you don't want that for you child.

Ok, without comment on his behavior. Ok, maybe I’ll comment that it sucks. However, he is the baby’s father. Your relationship with him is not his relationship with the child. If he chooses to see baby, be supportive of that.