So this person has fucked you before, and you still gave him or her the honor of your friendship? An old saying comes to mind. "Fool me once, shame on you. Fool me twice, shame on me." A scumbag that acts like a scumbag should be no surprise, and it is also not worth all the effort and emotion you're expending. Cut the loose ends, and leave it at that.
So Speaks The Gatekeeper...So It Shall Be!