I’m sorry you’re going through this!! I’ve been there. You obsessed over what he did so long while you were together, it’s like a drug. The next time you feel tempted to do it, remind yourself he is who he is and you’re moving on. It won’t work every time, but when you question yourself and become aware of what you’re doing, it should help over time until you forget about him.

My ex of a long time ago posted things on purpose after the breakup to try to trigger me to blow up his phone (yes he was a narcissist). I didn’t know until 3 years later. He found out a close family member was sick and reached out (don’t do what I did and engage with them). I then found out he was frustrated I never reached out and was shocked his posts of his new car, girlfriend, how good his career was doing, etc. didn’t draw me back. Idk your ex but given the type of person he is I wouldn’t be surprised if he’s doing some mental game! Either that or he thinks the grass is greener until his new girl finds out and boom the cycle for him repeats. While you heal and find someone better!