What to do?

It's over. He's going to do stuff in Europe. He's there for 2 months and I guarantee you he's going to hook up with different girls. Have some self esteem and self dignity and go for a different guy.

Break up with him. Plain and simple. He's going to keep cheating on you. Don't you think you deserve better then that?

I say break up and see what happens when he returns. Don't put yourself on hold for someone who is not doing the same for you.

leave him! if he wants other girls let him have them and let yourself have some respect and a fella who cares about you

if you want to have your self respect, then you need to break up with him (or stop seeing him if your not "official"). Because he obviously has no respect for you. And you deserve better than someone who doesn't respect you.

You have to let him know his behavior is unacceptable so either need to take a break and tell him that you need to re-evaluate the situation with him, break up with him completely and see if he comes back (also tell him why), or you can continue to forgive him and he will continue to do the same thing because you have allowed the behavior to continue. It is your choice honey, choose wisely because it can affect every aspect of your life. How do you know this girl doesn't have any diseases he could bring home to you? You have to protect yourself first!

I think you should stop seeing him because I think they might have some kind of arrangement like a friend with benefit type. I don't believe that he just happen to fall in bed with the same girl every time he is drunk. Usually, when a guy is drunk he will think of girl that he has a hot for and he would call her that would be you.