Owe the IRS!

I received the news the other day that my EX and I owe the IRS for our 2009 taxes. I was beyond upset. I was with him for 6 years, and this was the first time I had allowed him to do our taxes. I am doing what I have to to take care of the taxes owed. I have tried to get him to sign the paperwork, he refuses. Since he refuses I called the IRS to cover my behind. I sent them a letter explaining my situation, and giving them all of his information as well. I am hoping that this will get worked out. I was planning on using my return this year for my maternity leave, but I would rather get this paid off.

If anyone has dealt with anything similar to this situation, or have any tips, please let me know.