I think holding on to the idea of how others do us wrong creates a bit of a victim mentality (not saying you like to be a victim but in general there is adanger of getting used to feeling that way).

That’s why I think it’s wiser to switch focus from being a victim to being in charge. Unless you were abducted and was forced into something, you (hypothetical as many of us can relate to that) you decide to bring in and support jobless and homeless person who repeatedly lies and whom you only knew online etc We decide to enter relationships or pursue wrong people when it’s pretty obvious is a bad choice.

Rather exploring what he says and why he was nasty explore why you did that. And not in order to be angry but to understand yourself better, learn from mistakes etc Focusing on how he lies or that he perhaps loved someone more keeps you in a victim role.

He isn’t worth all this ruminating. He isn’t a great man but you are upset relationship didn’t work out. He is not the father of your children whom you have to put up with now. He was just a guy you unfortunately felt in love with who turned out to be a bad partner, likely face to face interaction was short and only lasted few months. It wasn’t even years of your life wasted. Your ruminating over him lasts longer than your relationship! It’s really not worth to waste another minute on it.