FTC has credit advice for spouses aniticipating divorce (excerpt):
If you’re considering divorce or separation, pay special attention to the status of your credit accounts. If you maintain joint accounts during this time, it’s important to make regular payments so your credit record won’t suffer. As long as there’s an outstanding balance on a joint account, you and your spouse are responsible for it.
If you divorce, you may want to close joint accounts or accounts in which your former spouse was an authorized user. Or ask the creditor to convert these accounts to individual accounts.
By law, a creditor cannot close a joint account because of a change in marital status, but can do so at the request of either spouse. A creditor, however, does not have to change joint accounts to individual accounts. The creditor can require you to reapply for credit on an individual basis and then, based on your new application, extend or deny you credit. In the case of a mortgage or home equity loan, a lender is likely to require refinancing to remove a spouse from the obligation.