Swingers?

So my boyfriend, boyfriends best friend, and I were all really good friends. Well my we were all together (not completely sober) and my boyfriend started initiating my boyfriends best friend to start touching my boobs and stuff. We ending up having sex with my boyfriend just watching. Now that I think about it completely sober I feel super weird about it and also now have major feelings for my boyfriend's best friend. I was honest with my boyfriend and he totally got pissed at me and said I'm basically a cheater! So in my opinion: don't swing!! It's super awkward and creates conflict!! What's your opinion?