Per Maryland Administrative Release #1:
"a military servicemember’s civilian spouse who is domiciled in a state other than Maryland and who is in this State solely to be with the servicemember serving in compliance with military orders is a nonresident of the State regardless of how long the civilian spouse has resided in the State, and ... is not subject to Maryland taxation on income for services performed within this State (e.g. wages, salaries or tips) "
Administrative Release No (marylandtaxes.gov)
If she has not done so already, your spouse should submit Maryland Form MW-507M to her Maryland employer to exempt herself from MD withholding.
TY-2021-MW507M.pdf (marylandtaxes.gov)
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
