If you are not divorced on the last day of the tax year, your filing status choices are

• Married filing jointly,
• Married filing separately,
• Or, if you qualify, Head of Household.  You are considered unmarried for HOH if you lived apart from your spouse for the entire last 1/2 of the year, You provide more than 1/2 of the cost of maintaining a residence for you and a qualifying relative and you have a qualifying relative (such as your child) living with you for more than 1/2 of the year . If the child is your qualifying child, you do not need to claim them as a dependent.

You cannot file as a single person unless you meet the strict definition of "legally separated" under a court decree, and your state recognizes legal separation.