I believe the only party liable for the mortgage is the person(s) named on the mortgage document. However, Arizona is a community property state so there may be some complications if the lender wanted to sue for deficiency on a non-purchase money 2nd mortgage. You are best advised to seek the advice of an attorney who can answer your specific question as it pertains to your specific circumstance.
Great question that would be best answered by an attorney that understands Arizona real estate and mortgage. The attorney may want to see the documents to get a complete understanding of your situation.
I would be glad to provide you with a couple of names if it would help you out.