Just because it sounds like there is a lot of money on credit and you owe a lot, I would most definently go with the paying down the credit cards and see about "slightly pushing" your ex-husband to pay more on the big amount that you owe.
As far as "being stupid" for having your ex-husband on a credit card or loan, you're not stupid. When you marry, you think that you are life partners and will share everything - debt, children, money, credit, and extra money. No one gets married thinking they are going to be divorced in 5 years. Who'd get married in that case?!
Hope this helps...
