Questions: Break Up & Divorce

So this guy named Kian and I are both freshman in college and we have been dating for a few weeks. This past Friday we both went to a party and got pretty drunk. When I showed up to his frat house, I found him but then didn't see where he went so I got scared that he had gone to the third floor with some other girl but he had just gone to sleep. I wasn't going to go to bed so I stayed up and all of my sorority sisters had left because I told them I wasn't going to leave without Kian, so I leaned onto my two friends Riley and Isaiah for support because I was pretty much left by myself since Kian was asleep in another room. During that time, Riley who is my (ex) boyfriend's best friend was trying to kiss me because he was just as drunk as me if not more. I had told him that it would be wrong to do that to my boyfriend, but other people in that house had spread a rumor that we had made out and my boyfriend got really pissed. We decided to go home and Kian would not talk to me so I called him the next morning and thought everything would be ok if I just talked to him about what happened but before I could he broke up with me and told me things were over between us because of what he heard. It's been a day since we've talked becaue I'm trying to give him time to cool off, but eventually I am going to talk to him and tell him my side of the story. He hasn't changed our relationship on Facebook yet so I'm hoping that's a sign that he's not completely done with "us" yet.. I honestly am so upset right now because I don't want to lose him and I just want to work things out without having to go through an actual break up. What do you think I should do with this whole situation? Anything helps, thank you!