^^^this.

He's preying on you when he knows you're scared, vulnerable and overwhelmed. The only thing to say is. "I was weak and vulnerable and you took advantage of that. I'm moving forward with my healthier choices. Please stop contacting me."

Remember that every word you say, every word you text, he will use to keep manipulating you.
Stop giving him things to hurt you with and to refine how he preys on you. He's going to keep doing this. The only way to make it stop is to get out of the relationship.