THE INNOCENT SPOUSE PROVISION
The IRS holds both husband and wife responsible for jointly-filed taxes, and for any penalties incurred from their joint return. If the IRS needs to go after a couple for delinquent payments, the IRS will pursue whichever spouse it will be easier to collect from.
The innocent spouse provision is the only defense against liability for return inaccuracies caused by a spouse. The provision requires proof that the spouse was unaware of any omissions of income or any other filing inaccuracy, or proof that the tax return was signed under duress.
Married taxpayers who file separately have three years to change their minds and file a joint return, as long as they are still married. The reverse, however, is not true. Taxpayers who have filed jointly can not elect separate filing status after that year's April 15, tax filing deadline.
It is also important to note that taxpayers filing joint returns prior to a divorce may be liable for a portion of a former-spouse's taxes. This liability should be provided for in any separation or divorce agreement.
Additionally, even though a taxpayer can not file an individual return after filing a joint return with an former-spouse, they may claim the refund on an amended return even if it is only signed by one of the original couple.