Unfortunately this is what others and I were worried about when you talked about moving into the apartment a while ago. Hurt people can say and do hurtful things. Even though you were on good terms when you guys came to this agreement, he now is clearly aware that he can use this agreement against you. Neither of you owe anything to each other (other than a bit of respect which he clearly doesn’t have for you 😒) but he now has power over you, and unfortunately he isn’t being nice about it.
I’m so sorry you’re in this position. It’s so sh!tty that your friends are in the middle of it too. I have to agree with @Lemongrass_ if any of your mutual friends are siding with him, distance yourself from them. I would also refrain from talking about what he says and does with your mutual friends, I know you’re just trying to vent and get support but if they’re going to report back to him and continue with the “he says she says” Shiite then it’s causing more harm than good. Try to keep that stuff to friends and family who aren’t friends with them. Sending love ❤️