These nightmares are a long-term effect of being repeatedly assaulted, they don't start immediately because our minds sometimes take years to start to process what happened.
That he showed concern does not make your feelings and perceptions void. Concern for one's partner in a loving relationship is the bare minimum, it is not praiseworthy - but he is also the cause of these nightmares.
Tangentially, while you may feel he is not a monster (many with lived or work experience may agree, others may call men that for their justifying rape), your trauma response has clocked him as a "monster" of sorts - a threat - because he is.
Due to his behaviour he is a threat to your wellbeing more than his comforting you after waking from a night terror is helping you.
You have said his behaviour has changed in good and bad ways, presumably to adapt to your "awakening". His challenging you whenever you try to put up boundaries. That's why your therapist probably thinks talking about the finances is a bad idea.
In theory Babyboomtastic it can work - it worked on my father and effectively ended his attacking his wife because he felt she could ruin his life going to the police. She documented all the bruises and cuts, started writing which helped immensely. She's still with him and hides her journals just in case. In OP's case I think the risk to her life is just too high, and there is no knowing what he might do.
You must not feel like you have to justify staying OP but NettleTea is absolutely right, do not overwhelm him with your progress, he might become unpredictable. I woukd probably not share anything about therapy. You're used to pleasing him and walking on eggshells for I fear very good reason, the downside is you simply do not know what he's capable of.
He does not want to start again, he wants you to start again and reset your brain so that he can keep doing what he wants because it works for him. You keep on working on getting a life that is working for you.