Most Helpful Guy
He still has feelings for you and is hurt. He wants to hurt you as well. Don't let him know he hurts you first off.
The biggest and best thing you can do for both of your sakes is to stay away from each other. It sucks, but the wound will never heal when the cause of it is always there. Explain nothing more to him. Don't talk to him or apologize. Just stay away from him. Yes, it means you will miss out on things if others won't make sure he isn't there. You two can't be around each other.
Let him heal and move on with his life. That part of your life is over, never to return, and some people you know may get lost as well. Sucks, but its a part of life.
The only way to stop hurting him and him hurting you is to stay away from each other.