Going against the grain YTA.

You earned yourself a retirement already from this. That's what you said. The legality of this all is irrelevant. The point of alimony is to support yourself because you were left in a shitty situation after a divorce, not as a way to seek revenge forever. The court order is just a technicality and a way to force your ex to pay, it doesn't make you not the asshole because it's legal where you live.

Unless he did something irredeemably horrible to you, other than the typical shit that happens when people fall out of love, then I say YTA. You don't need to pay him back anything, you can simply stop receiving money and you'd be totally fine; you've reached the goal for alimony. This is what you're telling us.

If I were in your situation, I'd be ashamed to continue taking money I don't need. This is especially true if your only crimes to eachother was falling out of love.