What a dick he is. Logically, people like this only do this to make themselves feel better, and it has little to nothing to do with you. Emotionally though, it bloody hurts doesn't it. I have been through similar with my gem of an ex-MIL, and her daughter. I went round and round in my head trying to rationalise it, trying to play out scenarios where I get to say my piece back, trying to work though it, but it just ends up being a cycle of repetative dark thoughts.
Now, when something like this happens, I book a bit of time in to properly think it through, once. When I'm done, I actively choose to make my peace with it, not because it's ok, but because there's nothing I need to do that's actually worth doing. (eg, MIL would never believe the truth even if it bit her on the nose, so there's not point trying to tell her. She can't spread any more lies without legal rammifications, so nothing for me to gain here) My time is better spent elsewhere. Then I refuse to think about it again, and replace the thoughts. Replacing is important, I can't stop thoughts, but I can push them out of the spotlight. If it pops into my head, I'll sort of go "Oh no, we're done with that shite, now, where did I get to with the meal planner / how long till that gig I'm going to / let's plan the new bathroom"
It takes a bit of practice, but I get faster at catching them, and better at redirecting the more I do it. The more I do, the less anvious I am, the less the dark thoughts start up.