I disagree with tclements73. There is plenty you can do about it. Given that neither ex spouse is able to refinance and buy out the other, tclements73, and swangie6063 both have the same course of action.
As you are both on the mortgage, you can both request and get the mortgage records along with your credit reports. Then you file an action in court to order the house to be sold. At the hearing present your evidence that you are on the mortgage, that it isn't being paid, and that it's hurting your credit.
The judge will ask your ex a couple questions about why he/she isn't paying the mortgage and then order the property be sold. The house gets sold, and you are off the mortgage.