I hate to be the bearer of bad news, but your x-wife will be in a heap of trouble. As a co-signer on a loan, the bank will look to her for payment once you file.
This happened to my Mom when my parents split up a few years ago. My Dad filed for BK and did not tell my Mom, and then my Mom started getting all kinds of calls and letters and had to file for BK herself because she was a co-signer on almost all of the accounts, mortgage included.
Also, my sister and I went in together on a furniture loan many moons ago when I was young and stupid, and when I filed for BK they went after her and it has taken almost five years to get them to stop harassing her. It was a nightmare.
So, unless you had something in your divorce decree that states your x is not responsible for the mortgage debt, you may want to tell her what is going on before she gets the letter from the bank asking for the entire balance of the mortgage like my Mom did.