This was really tragic and I'll say a prayer for your situation. I don't know the first way to advise you, this isn't my area of expertise. But I did want to say thank you for sharing because it gives others a lesson in what not to do, and what to look out for. Next time though, spare us the bleeps... it only serves to turn your situation into a comical one, when apparently, it is the furthest thing from.
You will always be tied to him while you are married. Being separated doesn't mean anything in a legal sense, except to a family court that requires an offical year of separation before granting a divorce. Otherwise... you are still married.
Heck, if you live in a communal property state and buy a car under your own name (not with his), he can still come by one day, pick it up, and sell it to someone else and keep the money.
The only thing you can do is get the Court to order him responsible for all of the debt. Once you have that, then you can take the court order to the cc companies and see if they will work with you. Sometimes they will, sometimes they won't.
The big issue I have with your story is...... When you got seperated and knew you had joint accounts with this person, why did you not knot take your name off!