I did "stuff" with a gay guy?

My best friend, he's really close to me and I've liked him since we met but the thing is he's gay. Yeah, it sounds pretty twisted because it is. I'm 17 and he's 18 and the funny thing is you would never think he's gay because he doesn't act like it at all and he doesn't go around saying this guy is hot and that guy is not. We were actually pretty flirty together but I guess people wouldn't consider it flirty because he's gay, so we would peck each other on the lips and just play around with each other like that. It wasn't until a few nights ago, we were at his house and I was lying on his bed using his laptop. He comes and lies next to me which is pretty normal and he's just lying there so I ask him whats up. He takes my hand and is just playing around with the gummy bracelets on it that have a "ual meaning". He asks me how many of them I've ever broken and what they mean. I tell him the purple one means hug or kiss and the black one means and I tell him I've never broken any of them because I'm not into that stuff; they're just for fashion. He's now laughing and he breaks a purple one and kisses me, like for real, not a peck like we always do but like a real kiss. I don't know what to do so he gets up because he realizes it's a mistake but I made the mistake of pulling him back and kissing him. From there, we just made out and we were about to hook up but we stopped because I'm not into that stuff. We both fell asleep and when I woke up, I drove myself home. Now, I'm pretty confused and I feel bad because I knew we shouldn't have done that and I have no clue what to tell him. We've talked since then and we hung out like normal and there's no tension and we haven't talked about that night but it just bothers me because he acts like there was nothing between us and I really liked him but I know that he's gay. How can I tell him that he's acting like an a$$ because he's pretending nothing happened. Yeah it's pretty twisted and i know people are gonna tell me, "You're in a deep fix, you can't change him; it's his choice," I just want to know what I can tell him because he's making me feel really crappy. (And I'm guessing he's not gay anymore right? lol)