Yes, they can become very paranoid and projection takes on a new level called "high". He may have looked at the credit card statement and saw the retainer charge and put two and two together, even though you've not used it.

Because you are pulling back and away from him, he's scared in his own way. So, what does he do? Starts acting out, etc. He wants to know what you are doing and w/whom. It doesn't matter that you aren't doing anything wrong, but to him, something is going on that isn't right w/you, so the snooping begins as well as accusations.

I'm very sorry that he's turned into Mr. Nasty, but he feels cornered/trapped and the guilt paranoia are feeding his internal fire right now. If he wasn't guilty about something, his reaction wouldn't be the way it is.

I know it's difficult living w/him but try to let some of this stuff roll off your back. Since he's brought up the divorce word, I would seek a consultation and protect yourself and your assets as much as possible.

Continue as you have been and let him put all of the papers in the doors that he wants. You can't convince him otherwise that no one is going in his little man cave.

Hang in there!

Sit quietly, the answers will reveal themselves when you least expect them to.
The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.