Hello. :)
Have been separated from ExH for almost 3 years, really amicably. We had worked out a separation agreement, and our divorce is almost finalised.
Suddenly, literally overnight, he announced he can no longer afford to pay maintenance. It was slightly over the CSA rate but we had agreed it together so I said, OK, just pay the CSA rate. He said he can't afford to pay that either. 
Basically, he says he has run up debts since we've split up, and that the Citizens Advice Bureau told him to stop paying me, because he wouldn't get away with not paying his rent, electricity, etc. Lovely!
He used to smoke spliffs every day but has just stopped. He says he's been going to N.A, and has "woken up" to how much he's messed his life up. But it's all coming out as anger, directed my way. He resents that I'm in the house (currently v cheap due to interest rates) while he has to rent a house; he resents that he has "overpaid" maintenance for the past 3 years; he resents everything, basically.
I don't know what to do.
Even more complicated... The house is his house but I pay the mortgage. He is adament he doesn't want to sell it. To help me manage during the time he can't pay maintenance, he offered to get a mortgage holiday. But when he spoke to the mortgage company, he told them we'd split up and he'd moved out - at which point they apparently asked him for my financial details before they'd agree to the mortgage break. I'm just dubious about handing those over - perhaps over-cynically.
We've always got on well and were happily apart. He has kids 35% of the time, and I thought we'd worked it out well. I don't know what to do now.
If you have any insights or brainwaves, do feel free to share! Thanks. :)