He broke a promise

He has done me wrong many many times, we’ve been together since we were 15 were now 21 and nothing has changed. I’m not going to get into detail because it’s a very long story but why does it still hurt every time he does me wrong?? I should be tired by now? Over him by now? And he doesn’t care at all, he doesn’t care about my feelings and says it. When we decided to give it a last try He promised to cut off ONE specific girl.. he promised me he would never speak to her again and that she was past.. well we only lasted 2 months and he got in contact with her again and hung out with her the next day.. his excuse was that shit happens in life that he has no control over, he said maybe they’re meant to be? I’m so confused he told me he loved me during that time and we still continued to hang out a lot, i still slept over with him a lot he showed he wanted something but says the opposite.. when will this cycle end?