Remember this,
Creditors don't care about divorce decrees. With that being said.......(forgive me Shogun......lol)
List out what debts you have. Make sure you organize it in such a way that you know what you are the joint owner on and not.
For the ones that you are not a joint owner on, forget about them. Only worry about the ones that you are a joint owner on. If you are an authorized user on any of his credit cards, call the creditor up and terminate the relationship. This will help you by protecting yourself from his poor judgment.
For your debt (debt that is solely in your name), start by calling the creditors up and explaining the situation and see if they can work with you.
We're here to help.