Many couples file their tax returns jointly to enjoy great savings. The tax rates for joint filings are lower, and there are more standard deductions as compared to taxes filed separately. There is a certain drawback, however. Both spouses are also jointly liable for every tax connected to that return, even if one of them is already deceased and the other is no longer earning for the family.
If this describes your case, the IRS can still go after you—after your houses, cars, bank accounts, and all other assets you and your deceased spouse have put up together. Had a separate status been filed, the debt would have died with your spouse.
Fortunately, you can seek relief through Internal Revenue Code § 6015, which provides that under specific conditions, you can file for an Innocent Spouse status. If the IRS approves your request, you shall be relieved of liabilities attributable to your deceased spouse.
In a nutshell, you have to prove that you did not know or could not have known that your former spouse failed to report his income, reported his income inaccurately, or claimed inappropriate deductions and credits. The burden of proof that you had no knowledge of these deeds lies upon you, so it would be wise to talk to a tax lawyer who can present your case more persuasively. A lawyer will also ensure that you do not miss any statutory deadline set by the IRS.