What is wrong with my friend?

Ok, today a lot of things happened. I got into a fight with my best friend because he thought i was rubbing my gf in his face, which I wasnt. He kept sending me messages on my phone and over xbox live cursing me off and trying to make me jealous of him, which he failed horribly at. He would not stop, so we fought and I broke his nose and beat him up pretty badly. So, after the fight, he came to apologize to me, and I accepted it because it was a good apology. Now, I found out that he is hitting on my gf and saying things like I love you too her and trying to break us up. I swear, he is one more word from me beating him up again if he doesnt stop. What should I do, should I actually beat him up again.