I have no idea what to do and in shock

Well last night my boyfriend went to a party with two friends, I dropped them off and picked them up due to the fact they were drinking. I has been talking to my boyfriend most of the night although he was drunk beyond belief, he had been texting me and then face timed me saying everything sweet you could imagine about how much he loves me and so on and during the FaceTime all seemed ok and his friends for in it to...fast forward to pick up time and I get there and he gets in then gets out and in the readies mirror I see him in an argument with one of his friends and the other friend( which was his gf) and that continues for a while. Finally they all get in the car, and his one friend is crying my boyfriend trying to talk to him and then the friends gf telling my bf to stop. As we pull into the apartment complex where I live and his friend just moved into they get our and my bf follows and they proceed to get into a fight. I then get told by his friend that my bf tried to hook up with another girl,