Assuming neither of you are dependents of anyone else, you can claim a non-relative as a dependent if:
(1) They lived with you for all of 2017.
(2) They had less than $4,050 in income in 2017.
(3) You provided more than half their support in 2017.
If you are not married, the person is not your spouse, unless you live in a state which recognizes common-law marriage, and you have held yourself out to be common-law married.
