needing advice...

Just november 10th my bf gave me a promise ring. November 13th he moved back into his moms so that we could try to get a place of our own with out roommates. November 19th his babymomma went to his moms house so that he could see his daughter. December 9th I found messages between him and his babymomma that were not meant to be had between exs. Saying that she saw on my profile that he and I were still together, that what he had told her that weekend was a lie, that she's 100% better then me, and that if he didn't stay at his moms and got his act together he couldn't see his daughter and that things between them wouldn't happen. Since he has had contact with her he has been very mean. Today he basically said fuck you that any plans for a future family with me because "he doesn't want to be a dead beat dad" and have kids only with the first person he had kids with. Truth be told his daughter is an illagitameat child because his babymomma drugged him and made him have sex with her. They weren't together until she told him she was pregnant. She even fudged the birth certificate to make her now bf the father of my bfs little girl. I no longer know what to do or how to feel anymore. Because he says part of him still likes her, yet she holds that little girl over his head like she is a trophy and tries to wedge herself between him and I. I've already talked to him about telling her that a relationship between them won't happen and that they are strictly parenting that little girl and nothing else. He didn't do it and is with her and his daughter now at a christmas party for his program called project everlast. Trying to get him and I a place to stay for just him and I. I have told him i will help him fight against his babymomma in court for custody and would help him take care of his daughter. I just don't know what to do anymore with how he is acting since talking to his babymomma. I need help