Feeling responsible for the disaster

I feel responsible for my own downfall, because he was Jekyll and Hyde from the very beginning. I made most of the effort to contact him, in an effort to prove that I was worthy of friendship, love, respect, whatever. Sometimes he'd grant me these things, and I was over the moon, that my misgivings about him were wrong. But now he has devalued and discarded me, and I have gone NC. Even my friends, family and shrink think that I had a lot to do with this, and that a mentally healthier person would have fucked him off as a sadistic loser a long time ago..... how do I cope with this?