I married last year on December 31st. Do I need to file my taxes with my spouse?
Based on the IRS guidelines, if you were married on the last day of the year, December 31st, you are regarded as being married for that entire tax year. You and your spouse are required to file your taxes as either Married Filing Jointly (MFJ) or Married Filing Separate (MFS).
If you are in the process of getting a divorce, but did not yet receive an official decree of divorce, then you are also still considered married for the previous tax year. In that case, you will most likely file as Married Filing Separate (MFS).