Leave or stay?

So I recently just found out I'm pregnant. My boyfriend of a year is very excited. But recently I've found out he unblocked his ex on everything and has been hearting her picture on Facebook. He was drunk when he did it but is that a valid excuse? This is the 4th time I've caught him talking to her again over the course of a year. I know he misses her and I feel like I'm not good enough because of it sexually and emotionally. After this time I really didn't get mad at her or him for doing it I just feel stupid because he knows I won't do anything about it. I read stories on here that sound exactly what mine sounds like and I think wow this guys a dick the girl needs to leave him even though she's pregnant. I don't have any emotion toward him anymore im not attractive to him physically and I really just am annoyed to be around him. But i feel like I can't leave because of this baby. I don't want to be a knocked up single teen but I know he's not good to me or for me and I deserve so much better. I'm states away from all my friends and don't have any family. Any advice on how to rekindle this relationship and try to forgive him for emotionally cheating and make it work for the sake of this baby or should I leave and do what's best for me? Please don't just say he's an asshole and I need to leave. I need real advice that can help me. The only reason I'm with him now is this child. I just really need help ladies 😞😞😞