If you are listed on the account and she files bankruptcy, you are liable for the amounts on the cards.
You may be able to get a portion discharged in the bankruptcy.
Speak with an attorney in your area.
If you're listed exclusively as an "authorized user," then you may be okay. If you are listed as a "co-debtor," then you're probably going to get stuck with the debt. One would probably have to contact the credit card issuer to determine their status. Please note that nothing in this posting or in any other posting constitutes legal advice; this is simply my understanding of the facts, which I do not warrant, and I am not suggesting any course of action or inaction to any person.