He has completely separated all of his accounts from mine. Bank, phone, everything.
Ummm...Abbey? Just what do you think this means?
He's been renting a love nest/escape hatch for a year, he's separated all his finances (could he be hiding other financial misdoings from you?). Just how deep into the sand do you plan to stick your ostrich head?
What reasoning does he offer for separating his finances? Please, please, please protect yourself financially. I've seen way too many women here try to woo their H's back by being lenient about financial matters, and it always comes back to bite them in the butt. You carried the financial weight while he was spending his time working for free for OW and paying rent on his love shack (just think how nice it would be to have that $8,000 in your pocket right now - that would pay for a helluva vacation!). Don't let yourself get scr*wed financially going forward.
Is he paying half of all bills? Are you making him pay you back half the cost of his other place? Do you know how much money he's making now?
