He hasn't 'won' though... you have! You are the bigger, better, more mature person in this.
You have every right to feel hurt because what he has done is wrong and realistically you are mourning the loss of a close friend. I know he has done wrong and in no way am I justifying what he did, but remember those good times you shared. Enjoy those memories, just because he is different now doesn't mean you can't enjoy what you used to have.
I'm sorry for the way that he has turned out, I know how lonely a person can get. Just remember, you are the stronger person.

Take care