So this guy that I have been talking to for a long time, which was practically my boyfriend was hanging out with another girl, and never told me. So to make this story short, he cheated on me. And I forgave him...

This weekend, I drove 3 hours to come and see him... and everything was fine and we went to his buddies house to hangout. That's when he started acting funny and everything and basically made me feel like shit. Which, I then started to think about the girl he cheated on me with, and I was a little drunk so I opened up to his buddy about it... and his friend ended up telling him.. and we got into this huge argument and he made me feel like complete shit and was talking down on me.. so I slapped him for it. And he slapped me back as hard as he could... then proceeded to tell me to get an uber home.

Later he apologized to me, and said ever since he was little he told himself he would never hit a girl and he said it was only instinct that he hit me back... because if someone hits him, he hits back... 

I forgave him... but, I'm still upset about the girl he cheated on me with and I know they still talk.. and I'm hurt at the fact that he hit me because growing up I watched my mother be abused by my father and he knows how I feel about it..

I just don't know what to do.. should I just forget all of it and move on and forgive him for hitting me because he didn't mean it? 

Please help 

And yes I realize that I slapped him first.