TC, if what you claim is true, then it's not you who's at fault, it's her. As long as you remember that how you live your life should not be dictated by the emotions or will of others, you'll notice that you've actually been granted freedom from this person. You seem like a man of virtue, especially committing to her alimony and that's a sign of a man of virtue. Let that lift you up, knowing full well that you consistently did the right thing.

You can't control how others treat or feel about you, but you CAN control how you react and how you feel about yourself. Practice being virtuous and you'll notice how you're actually more stronger than you'd imagine.