8506 / What does it mean to be considered unmarried for purposes of determining filing status?

Taxpayer filed a separate return;

Taxpayer paid more than half the cost of maintaining the home for the tax year;

The other spouse did not live in the home during the last six months of the tax year;

The home was the main abode of the individual’s child, stepchild, or foster child for more than half the year (except for temporary absences);

Taxpayer satisfies the criteria for claiming the child as an exemption (or, prior to 2018, could not claim the exemption because the exemption was transferred to the non-custodial spouse). Note that the exemption itself was suspended for 2018-2025.¹

1. IRS Publication 17.