@Smichael73 while you are still legally married (and appears there is no such thing as 'legally separated') in your state, the IRS does have a sub-category of "married", called "considered unmarried". you must have lived apart from your spouse for at least the last 6 months of the tax year.
look at the middle of page 8
https://www.irs.gov/pub/irs-pdf/p501.pdf
