Paying him? For what? It doesn’t even make sense.

First of all it wasn’t a loan and second of all you cannot appease people like him. And why?

He is going to sue you? For what? I really don’t understand this. Is there more to the story?

Block him and cut all contacts and if he keeps bothering you, then get law enforcement and lawyers involved. You can’t really ask for restraining order if you intend to have zoom sessions with him and sending him letters. Cut him off and let the lawyer deal with it if he demands things. Cease and desist and move on.

He was a boyfriend. Not a husband. You have no kids and no property together. Prolonging contacts with him is unnecessary and he has no legal power here at all