My soon to be ex-husband and I were married in the state of Texas. Before we were married he told me he was current on his child support, needless to say he was not. He lied to me and when I filed with him, the IRS took my return since he was not working "legally". He receives Disability and works on the side--mainly jobs that pay him cash and cannot be tracked by IRS. The IRS says I am responsible to pay his back child support. Take into consideration that I have not adopted any of these children. Am I responsible even though there was trickery involved?

No, your part of the return can not be garnished, there are special forms ( injured spouse) that you file. Or even file married filing separate

I find it very hard to believe the IRS actually told you this