@Quantus: Solid advice despite your rank!
Additionally to what @Elf said, it seems like the guy is genuinly hurting. It is no excuse for his behavior, but it might give you a little insight. I know you are pretty open with your sexual orientation here, but I do not know if you are IRL. And even more, if the other guy is. He might be really afraid of others to know and also not being sure about everything himself. He made himself very open to you and is just terrible at handling this rejection. Of course this is his own problem and you are just suffering because it is hard for him to get through this.
My advice would be just to distance yourself from him. Give him time and space to figure things out. If he gets mad or is rude, just ignore it and don't let yourself get dragged into discussions about The Incident. Its pretty easy to say this but I guess it might be quite a bit harder to do. In the end it is his decision: be your friend or completely break off the friendship. But all of it will take time.