<human>: I'm 20 f and my bf is 22. A couple of weekends ago we broke up but just recently decided to get back together. We've been taking things slowly though. And on Tuesday we hung out for the first time in awhile. A bunch of people end up coming over to his place and everyone getting drunk. 
My bf and this girl start talking (she has a fiancee that isn't here with her), and my bf is pretty wasted and I am too at this point. It looks like she's coming on to him and he seemed pretty receptive of it. In my drunken brilliance I decided I will initiate a threesome so keep from him cheating. 
Well things start happening and I realized in a moment of clarity that it wasn't right and I didn't want to do it, especially since things were so fragile with my bf and I. So I get up and make a huge scene and stop things from going further and he gets mad at me and locks himself in his room with her. So I'm out side of his room getting more and more upset to the point here I'm throwing bottles and plotted plants around and his roommate has to forcibly take me home.
The next morning while I was still a bit drunk I messaged her fiancée And told him everything, and also said I thought they slept together. Everyone says I was in the wrong for that, but I felt it was the right thing to do.
 A few hours later my bf came over and he was adamant that he didn't have sex with her, and that they passed out after I left the room...
The whole night is just killing me and I'm not sure what to do with us.

Can you condense the text into three sentences or less?
<bot>: got drunk with bf, initiated a threesome and then stopped it. Bf got mad and locked himself in the room with other girl but say they passed out.