Legal Question in Real Estate Law in Maryland

If you can afford it, make an offer to buy her out. It sounds like there isn't a whole lot of equity in the property at this time unless you made a large down payment. It's obvious from your scenario that her moving back in isn't a good solution. If she wants half the rent, tell her to reimburse you for the mortgage payments she defaulted on. If you can't work something out, either of you could go to court and file a partition action, asking the court to appoint a trustee to sell the property and determine who is entitled to what part of the proceeds, but this is an expensive procedure and you'd both end up much worse off than if you could agree on a buyout or some other resolution.