If you file a joint tax return, you will be liable. The only exception to this is known as the innocent spouse defense. It holds that one spouse cannot be held liable for the wrongdoing of the other if the innocent spouse was ignorant of the wrongdoing and did not derive any benefit. That is rarely the case because spouses often talk and there is usually a benefit to the other spouse by receipt and use of the income.
I am not a CPA and you should consult one, but I believe you can file married but separate. There is no liability in that event for the debts of the other.
In divorce law, it is another matter. All debts incurred during the marriage are marital debts. Again, the only exception is when the other spouse did not receive any benefit. I assume that is not the case here so she can seek a credit or your contribution for the taxes even if you file separately. But at least you won't owe the IRS.
Answered on Mar 07th, 2013 at 8:34 AM