To heck with all the kibitzing.
Only your ex is liable for the debt to the lender BUT depending on the divorce decree you may or may not be liable to your ex for some share of the debt.
Be aware though; if the lender finds need to foreclose on the mortgage, you will be listed as a party to the suit. Since you do hold a legal interest in the property (your name on the last deed provides for this), they must include you in a suit to foreclose. You will not be held liable for the debt but the lender cannot just take away your interest without a courts invovement.

