Horrible experience. I am so sad. What do I do now?

Sorry, but having read this twice I still cant understand what you are complaining about. He made out with a guy for a bit of fun because someone asked him to. And? Why were you embarrassed? Why are you super pissed? I just dont understand. He didn't cheat on you with the guy, it was a joke, because someone asked him to, and you two just agreed that you are not even dating yet. Where is the problem?