Spouses going through a divorce may have concerns about their filing status. In general, spouses are married until the judgment of divorce is entered by the court. If the parties are married as of December 31st, they may take advantage of their Married Filing Jointly tax status. (IRS Reg. 1.6013-1) This is true even if the court has entered a temporary order and the spouses are living apart. (IRS Reg. 1.6013-4)
Talk to your accountant for more and updated information and specific advice about your situation.