Am I wrong?

My boyfriend and I used to be friends with benefits for 2 months (March to April). In May, I was leaving to go home for spring semester and the last two weeks in had left, he treated me like shit. I caught feelings in our time of being FWB. He did too. I wanted to be in a relationship with him and he told me that he didn’t want that. We acted like we were dating but then he suddenly switched up. The weekend before I left, there was a Grad party. His friends came to visit him from out of state. This same weekend he told me that this was the end of us being anything. At the party, I got drunk and danced with everyone. His friend that was visiting was making moves on me while dancing and was trying to kiss me. I said no. I saw him at the party and while I was drunk I pulled him in the bathroom and tried to confess how I feel about him and he told me again that he doesn’t want me and to let him go. I was so hurt and went back downstairs to dance and drink some more. I ended up kissing his friend. Just a kiss. In July, he visited me at home and told me that he really wanted to be with me and that all this time he was just confused and wasn’t ready for a relationship. We talked some more and realized that we wanted to get serious. Now we are official as of September. He recently asked me if I ever had anything with his friend and I couldn’t lie so I told him the story and he is angry with me. He has been crying and has been asking why I had to kiss his friend and cheat on him when we were exclusive and all this other stuff. First off, we were not exclusive and I didn’t cheat on him but I was wrong to act out of spite. I was also drunk. He is so angry and I don’t know what to do. Is he overreacting? I have apologized over and over but he is so hurt. Am I wrong ?