Any advice for a young mother who just had a long term boyfriend want to break up?

I am a 20 year old of a one year old and my boyfriend, who I have been dating for 6 years, wants to break up. For those 6 years, we have been in love and of course we have ups and downs. After moving 2 hours away from our hometown and having a baby, we found ourselves facing financial difficulties and stress. I still haven't found any friends around here and so with all the stress and everything, I have no one to talk to and no way to "de-stress" myself. He has tons of friends and goes to the bar or club once or twice a week. well, a few months after the baby was born, he decides to go out more and more and more as well as stop doing anything with me (at home or take me out)? I dont know what to think about this... why he did what he did and why he wants to break up. i know we have been arguing way too much with the new life of young parents, but he never wants to talk and just run away from problems. we have so much history together and we were more than just boyfriend and girlfriend. why all of a sudden did he want to leave? our daughter is 13 months and we have been seperated for 3 months now and still living with him is making everything 10X worse, considering he has a new best friend who he hangs out with almost every day... she has a girlfriend though. please help me out with this situation... i really want to be mature about things and work everything out, especially since we have a child together. (advice from guys would be great as well!!! ;-))