No, if you file a separate tax return, you are only liable for items on that tax return and income items reported in your name/social security number.
Married Filing Separately is a penalty type filing status. Many tax credits are unavailable: Earned Income Credit, Child care credit, Education credits. Several deductions are lost: student loan interest deduction, tuition and fees deduction, savings bond interest exclusion.
The biggest limitation is that MFS status, both spouses must either use the Standard Deduction or Itemize - Sch A. their deductions. If one spouse Itemizes the other spouse must also, even if they have no itemized deductions.
If children are involved, then the Filing Status Head of Household may be available, even if still married. To use Head of Household status one must: 1. file a separate tax return 2. taxpayer paid more than half the cost of keeping up his/her house for the year 3. Spouse did not in the home the six months of the year and 4. taxpayers home was the main home for more than half the year of his/her child or stepchild.
For previous years tax returns that have been filed jointly and signed. There are options regarding joint liability: Injured Spouse Claim - Form 8379 Injured Spouse allocation and Innocent Spouse Relief - Form 8857 Request for Innocent Spouse Relief. These cover situations where one spouse has outside debts that may collect a joint refund and situations in which one spouse cheated and the other was not aware.