Legal Question in Credit and Debt Law in Pennsylvania

Yes, of course you are. You are a co-signer. When you agree to be a co-signer on a loan for anyone, you are in effect saying to the lender "if the primary borrower does not pay I will pay so go ahead and make the loan." Divorce changes nothing. If I were you, I would go and get a divorce attorney and get it written into any separation/settlement agreement that this debt is the responsibility of your wife and that she either has to refinance it out of your name or get it paid off and she has to indemnify you if you end up paying to protect your credit.