I feel hopeless......................…

okay, so to make a long story short. I met my now boyfriend 2 years ago when he started working at my job. We hit it off instantly not anything romantic just really good friends. At the time he was dating someone but still having some trouble with his previous girlfriend whom now is his baby's mother. Things for a while with us were strictly platonic, he was there for me to listen to my problems as i was for him. We hang out we talked all day things were great. Last summer things got kind of weird for us and we stopped speaking for about a month, we finally got back in touch and it was then he told me he had a child on the way. I was quite shocked because it was with his has whom now he had been broken up with for over two years. He explained to me he put himself in a situation he shouldn't have but he now has to own up to his responsibility which i respected. I was there for him throughout the whole ordeal, his baby mama stressed him out her entire pregnancy because she thought that because she had gotten pregnant they would rekindle their friendship but he said nothing would ever want to me him work things out with her. Ok well now the baby is here, after all this time we started to see that we have real feelings for each other and we began dating. He is a awesome guy, sweet, kind hearted, generous, respectful just all around great person. The only problem is the baby mama calls non stop for no reason, every other week he's threatened with he will be put on child support even though he has been there since the beginning doing everything he can even purchasing maternity clothes to make her feel comfy. From time to time she gets upset and asks him why he could he not tell her he had a girlfriend, on several occasions he told not to bring "females" around "her baby". She got mad and told him not to get her anything for mothers day, he did anyways and I feel like it led her on because now she feels like she has to get him a gift for his upcoming birthday. I feel as though he is to nice, he doesn't seem to really put his foot down with her and it bothers me. I don't know what to do, apart of me wants to be with him and apart of me is telling me to run for the border. I understand that this woman will always be apart of his life and this baby will always remain his number one priority but sometimes he makes me feel as though he will always have trouble with her until she finally moves and gets a man....she did not move on after two years of being broken up and she is definitely not going to let it go now that she has his child....what do I do?