Can a creditor come after me for a lease that my exhusband incurred without my knowledge while we were married?

I am a lawyer in CT that practices in this area. 

As a general proposition of Arizona law, either husband or wife has the statutory authority to incur debts for the benefit of the community. Wife may purchase a new Mercedes under her signature and without her husband's knowledge, and the payments for that Mercedes are the liability of the community composed of the husband and wife.

Arizona, by statute, recognizes two significant exceptions to the statutory authority of either spouse to bind the community: first, liabilities under personal guaranties and, second, most real estate transactions. Arizona statutes exempt (with a few exceptions) any transaction for the acquisition, disposition, or encumbrance of an interest in real property and any transaction of guaranty, indemnity or suretyship.

Therefore, your situation is analogous to the car example and you may therefore be liable if the lease was for your benefit too.  I would talk to a lawyer in your area and not respond to the collection calls unless a suit is filed.