I'm pretty sure that if both names are on the mortgage both parties are responsible regardless of the M. Only way that changes is through a resale or refinance. The deed is a completely separate issue and a party can selectively wave their rights to the property.
What would be a prudent move would be during the course of the D to force a sale or re-finance. You could always give her a specified period of time to sell. Problem is as long as you are on the note you are responsible for the payment.
I'm not in your shoes and my W is being generous by giving me time to refinance. Three years in fact. In return she gets to claim 50% of any profits (loses) if I choose to sell between now and then.
Fun stuff.
_________________________ Me-41 W-39 M-15 yrs T-17 yrs D-12 S-9 S-8 B 5/08 S 1/09