 This is Washington's news traffic and weather station, WTOP. WTOP News. It's 7.52. Same-sex marriage in Maryland has been on the upswing since a decade ago when it was first legalized. The US Census Bureau estimates there were about 4,400 same-sex married couples in Maryland in 2012. That's the year before the state made it legal. That number grew to more than 10,000 by 2015.