I would need a few answers to additional questions to be able to recommend the best options.
Are you still in amiable relationship with your ex-husband? If so, have you mentioned that he should explore his options as well as your concerns? If he wants to stay in the home he may have an option to modify the loan, and if that were a possibility you could possibly be removed from the loan, in that scenario he could stay in the home which might solve the problems and keep everyone very happy.
IF he doesn't want to stay, maybe you could move in and modify the loan and stay, if neither of those scenarios are of interest then the next thing to review would be a short sale, there are many consideration in completing a short sale and you truly need to research any tax or legal consequences that may be applicable. The Arizona Association of Realtors created a great document which is a seller short sale advisory and has links to many of the important factors, I would be happy to provide one for you if you wish, of course a CPA and Lawyer can be of great assistance regarding those two categories.
If a short sale is a good option then the first one to consider would be a HAFA program which can allow for relocation assistance to the occupant, maybe that is what would help your husband to consider addressing the problem.
Worst case; I have seen where a husband was awarded a home, the wife is still listed as a party to the loan, she was able to repair her credit within a reasonable time frame with much effort, documentation and consultation with the appropriate parties.
On a side note, I personally think divorce judges should be hung out to dry for approving an arrangement like you got. With your name off the title to the house, you have absolutely no say-so whatsoever in the disposition of the property. And yet with your name on the mortgage loan, your credit will always be at risk, based on whatever your ex-husband does - with no say-so or power whatsoever. I'm just sorry you didn't have legal counsel before that happened.
Best of luck to you!
You need to seek legal advice and a CPA. A short sale could be the best option if he will cooperate, and then you could purchase again in 3 years as long as all other credit is managed well.
Feel free to contact me for guidance in the process.