I actually think you've dealt with this in the right way.
At the start of this thread I was one of those thinking 'why on earth wouldn't you just ask him???', and that's probably what I would have done in your shoes too.
But actually, I think your freeze instinct has helped you here. I know we'll never know for sure, but from what you say it feels likely that if you had done any of the responses on here and asked him about it, he would have likely been expecting it, and would have said something like 'Yeah, it's because of that financial issue I told you about...that's why I've been decluttering, right?'.
And suddenly OP is on the back foot. Maybe he wouldn't be so brazen in gaslighting as to say he'd already told her about it, but she would be coming to him looking for answers, and he'd be in a strong (psychological) position.
Plus, she'd then probably (and justifiably) react in that 'mad' way he said he was expecting, by saying 'Why on earth didn't you tell me??? Why did you hide it???'. And so suddenly he can go 'Because I knew you'd react like this, and see, I was right!'. It's all so manipulative, and very possible that OP would be questioning herself and her reactions, rather than realising what a piece of shit he is.
So by trying to process it all, and work through the scenarios to realise there is NO suitable answer he could give her, OP has done well to instead drop the rope and step back. He's then had to be the one to make that eventual phone call, because he's wondered why she hasn't said anything.
She's in the stronger position of now better questioning everything he says, as she's been processing it all day, and better able to see through his bullshit. And so she comes out on top, being rid of him.
(Disclaimer - obviously the above is all speculation, but from what you've said, it doesn't sound unlikely a scenario at all)