How do you not want to cut yourself or jump off a bridge?

I wanted to post about all the wild one sided things my exFP is saying about me but no, I dont want this to be about what he's doing. I want it to be about what I can do to not let those words hurt me. I don't want to give him this power.

When someone has decided you are a monster and is picking a part every little thing you've said or done to prove it, how do you not let it get to you? What do you say or do that helps ease your mind? I feel so vulnerable to his criticism because he knows me the best.