Maryland has no 50/50 rule. Section 8-205(a)(1) says that after the court determines marital property and its value, it is allowed to transfer ownership of an interest in property, grant a monetary award, or both. The court does this as an adjustment of equities and rights concerning marital property. The text sets no percentage.
Section 8-205(b) lists eleven factors. The court considers them when it decides the amount and method of payment of a monetary award, or the terms of a property transfer. The table below lists all eleven.
Marital property comes first. Section 8-201 defines it as property acquired by one or both spouses during the marriage, however titled. It excludes property acquired before the marriage, property acquired by inheritance or gift from a third party, property excluded by valid agreement, and property directly traceable to those sources. Part of a house is sometimes non-marital. Ask your attorney how that applies to your house.
Your next step is paper. Write down when you bought the house, where the down payment came from, and what each spouse put into it. Bring the closing statement and the bank records to your attorney.