Married individuals who file joint returns are each 100% liable for the tax reported on the 1040 return, even if the other spouse earned all of the income. This means that the IRS can collect all the tax from either spouse, and it does not matter if they later divorce.
The only exception to this 100% joint liability is the Innocent Spouse Rule. The IRS may release the innocent spouse from all or a part of the 100% liability for the joint tax return if the spouse can show (1) the tax understatement was not their fault, (2) the spouse did not know or had no reason to know that there was an understatement of tax, and (3) it would be unfair to hold the innocent spouse liable.
More stringent rules apply, however, to tax debts before July 22, 1998.
You do not have to be divorced in order to apply for innocent spouse relief, although in some cases it may help.
When the Innocent Spouse Rule applies, it can be a real lifesaver. We can professionally assist your application for innocent spouse relief.