I hurt my best friend beyond forgiveness or apology
Thats a shame. Why would you hurt a friend this way?
He had a history of unexplainable betrayal.
It sound's like this friendship is over and I don't think you are in the wrong for cutting him out of your life if he has a history of betraying you. There is no reason to keep this friend if he keeps dragging you down.
I knew he was bad news. His betrayal coming from different directions more than once was more than I could handle. I'm glad to be clean from his manipulative behaviour.
While it sounds like its a good thing to be free of this friendship, next time just end the friendship without needing to hurt them. That way you can get away from the toxic friendship without any of the drama.