Legal Question in Real Estate Law in Maryland

You are under no obligation to relinquish your ownership interest in the property. If the mortgage holder wants to sell the property and you are unwilling to do so, he/she could file a legal action seeking a court order appointing a trustee to sell the property. They would also ask for an accounting if they have been solely or mostly been responsible for maintenance of the property (e.g., the mortgage payments, taxes, etc). This would be to get the court to declare that they would be entitled to all or most of any net sales proceeds, depending upon the relative contributions of the owners. If the deed describes your ownership interest in the property as "A and B, tenants in common", you have a separate interest that you could leave as part of your estate, or transfer to a 3d party, although then your transferee would just be in your shoes with respect to the mortgage holder/co-owner. If the deed says you and the co-owner are "joint tenants with right of survivorship", whichever one of you outlives the other will automatically become the sole owner upon the death of the other.