IRS rules for "considered unmarried"

rec123

I'm in the middle of a divorce. My spouse moved out of the house in June 2023, and I have sole custody of our 2 children. I am essentially the only one supporting the kids and paying for the house. He only pays $40/week in child support and no other contributions towards the mortgage, etc.

My understanding is that I meet the IRS definition of "considered unmarried" and could file as head of household for 2023. If I do so, what filing status would my spouse have to use? Do I need to do anything to prevent him from trying to file as head of household himself?

He purposefully (and without my knowledge) filled his W4 out to have almost no federal taxes withheld last year, resulting in a very large tax bill for 2022. I adjusted my withholding for this year to prevent that again, but do I have any liability for his taxes owed for 2023 if we do not file jointly?

BradyP

In this case, your spouse would use the "single" filing status if they do not meet the requirements of any other filing status.

Unfortunately, there are not any preemptive actions to dissuade your spouse from using a filing status they cannot use, however, if each of you claim the "Head of Household" status and claim your two children, the IRS will reach out to each of you after filing your return asking for proof that you are able to claim the head of household status, this would include custody agreements, child-care related expenses, etc. The IRS will then determine out of the two of you who is able to claim the "head of household" status and ask the other to change their return accordingly.

If you do not file jointly, you would have no liability for his unpaid taxes.