As stated, if you provided care in your home for a qualifying person, usually your child dependent, then you should qualify for head of household status and don’t need your spouses Social Security number. (If you have not been troubled by lack of Social Security number before, I wonder if you might have had a dependent in the past who is not a dependent this year.)
if you don’t qualify for head of household, you must file as married filing separately. You can’t e-file if you don’t have the Social Security number. You have to print your return and mail it in, and attach a written statement giving your spouse‘s name, last known address, identifying information that you do know such as a birthdate, and explain why you are unable to provide the Social Security number.
you might have to provide the program with a fake Social Security number before you can print your tax return. You can use 999-88-9999, but you must remember to white this out on the printed copy before you mail it.
