Don't look back. Your mind will play tricks on you. You will lie to yourself, tell yourself that “maybe it can work” and “maybe I was wrong” and “if I just try one more time, maybe he or she will change.” No. That is not happening. They aren’t going to change. And the fact of the matter is, the more you crawl back to them, the more you belittle yourself and push them further away. Don't do it. Walk away. Don’t look back.