She has none over the agreement you have with the tenant--however, as your spouse she has full rights to the home itself until a court otherwise rules in a separation agreement of final divorce decree. You MAY have exposed yourself legally to the tenant depending on whether the lease itself is legal under MD laws governing room rentals (I am NOT a MD attorney) and whether the agreement is oral or written (and therefore provable in court).
I would argue your spouse has full authority to demand the tenant be removed from her property--that is an option that COULD further expose you legally.
Recommend you consider negotiating the tenant out of the property on terms you can agree to. If you try to keep the tenant and force an issue with your spouse--I think you're going to wind up on the short end of the stick. If you decide you need an attorney, I can recommend a MD attorney Brandy Peeples at http://www.avvo.com/attorneys/21701-md-brandy-peeples-1557706.html
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