@Critter-3
I think you are mistaken. The regulations and publication 501 do allow a married person to file as single if they are “considered unmarried“ according to their state law. The problem is that almost no one under a legal separation is considered unmarried under state law.
Unmarried persons.
You are considered unmarried for the whole year if, on the last day of your tax year, you are either:
State law governs whether you are married or legally separated under a divorce or separate maintenance decree.
Single
Your filing status is single if you are considered unmarried and you don't qualify for another filing status. To determine your marital status, see Marital Status, earlier.
