What do you do if one spouse defaults on a debt that he or she has agreed to pay in a divorce?

You sue him or her, and you will have a legal document to back you up, just like you would with any other person. Divorce itself is just a business transaction, but it has family implications. The creditor can still come after you, and they probably will, but even if the creditor succeeds in getting money or property back from you on a debt that your ex promised to pay, you can use your divorce agreement to sue for breach of contract. Your divorce agreement, once signed, is a binding agreement so that your children don’t have to go through continued upheaval and can instead adjust to a life circumstance they already didn’t choose.