My husband was previously married, and was in a similar situation. His ex sent a certified letter demanding a refinance... when we spoke with a lawyer, he helped us draw up a reply letter that stated that not only was he not legally obligated to refinance, but that he had already tried multiple times (at the time, we wanted to refi and put it in our names together to get her off of the loan) and the bank was refusing. In the letter we gave her the option to fill out a quit-claim (or interspousal transfer) deed to have her name removed from the deed... then we could submit (together) that and the divorce documents to the bank. Some banks and lenders are willing to work with divorcing couples when they provide that info.
His ex refused and called him and made many threats - then called back a week later to say that she had been wrong, she contacted the bank as well only to find out that they laughed at the idea of refinancing...
Just some background as to what our lawyer said (we are in california)... but every divorce decree is a little different, so I would agree with getting a lawyer to take a look at it... some lawyers will actually give you valuable advice over the phone without charging you a dime... just make some calls!!!

