I think you realize, yourself, you need to cut the cord. Maybe, he's already cut it. You're still hurt about what transpired when the two of you were a couple. You call him your "ex," but a lot of your current pain seems to be rooted in when he was your boyfriend. You seem to need him more than he needs you. That's a horrible position to be in. A friendship where the need is not mutually balanced can become a toxic thing. I speak from experience. Try to really let go. Try to give up on having some kind of last word, whether to express resentment, or to apologize, or to say you don't want to hurt him. He mainly wants you to just leave him alone. That's awfully hurtful. You're looking, I think, for some kind of closure. We don't always get that.