You might be HIS best friend, LYF, but he sure isn't yours. A real friend doesn't do this kind of stuff.
You can care about people but not have them in your life. Someone who hurts you can have your compassion, but I'd think very seriously about giving them anymore of your time.
While I'm not going to argue that we have some responsibility for the way we allow ourselves to be treated, I have to ask, Why isn't the person you are "really, really mad at" him?