I feel your pain. I understand debt. I understand a H not dealing w/it. We are nowhere near your level, but my H has ignored the filing of taxes, and now we're "fixing" it.
One thing to remember... If you remain married, eventually you will BOTH have to deal with the debt, together. If you separate/divorce, eventually you will BOTH have to deal with the debt, separately.
He's going to have to deal with this debt sooner or later. Or "things" he owns, has loans on, etc..., will start to go away.
How can you deal with this in a way you are comfortable with?
His inability to man up and handle this unfortunately puts it on your shoulders. I guess you just need to figure out how you can handle it in a way that's best for you and the kids.
Good luck, friend.
PS - I think the rest of R/M stuff is unable to be dealt with until the financial stress is either handled, or on a path.
I am debating whether we should file for bankruptcy together or legally separate/D and take our own debt. I could manage my debt especially if I ask for a little more alimony in exchange for keeping my paws off of his valuables...
The money issue SHOULD have been dealt with before he left as it is the elephant in the room. He has more of a start fresh approach and throw the baby out with the bath water. Meaning, it was our R that led to his overspending and debting. I have to give up on trying to evolve his thinking.