I am about to make this sound a whole lot easier than it actually is. And I acknowledge that, so take it for what it's worth.
It pains me to hear you say that you feel like you need to make the decision about D or not. Take that off of your plate right now.
You are not getting what you need to heal. This isn't about him and what he thinks you should need. It's your healing process from countless wounds that he inflicted. You are the only one that can decide when you have enough.
I suggest writing down what you need from him and what you need to feel (emotionally) in order to stay and believe that it can work. It can be questions you need answered, t can be an open ended allowance to ask questions forever if need be, it can be coffee every morning or hugs every night- tell him what you need and what you are not getting.
Tell him it is non negotiable ad you will ok longer allow him to dictate what you should be doing or not. You are in charge and it is up to HIM wether you stay or not.
I had a few and I was very clear - just a few examples- NC was HUGE for me. And, he needs To answer any question I have, whenever I have it with complete honesty and no heavy sighs or eye rolling FOR AS LONG AS I NEED TO ASK THEM. There is no time limit.
He agreed, and so far he is keeping up his end of the deal. I told him I didn't want to make him leave, I was willing to work in R, but it had to be on my terms. I would be heartbroken if he left, but I would be okay. Once I said that, and showed him I meant it, he was on board.
Pardon my intrusion, but HOW DARE HE MAKE YOU FEEL BAD FOR NEEDING ANSWERS. And how dare he mock your strategies (the letter).
Please do not allow him to make you feel bad or guilty or crazy for needing things from him.
I would definitely read up on 180. And I would try to find the strength to understand that it is his turn to earn you back. He can either meet your requirements, or he can walk away. His choices got him here, his choices can decide if he stays or not. That is not on you.
I wish you only the best. And peace. I truly wish you peace.