You and Ghost were both on Task Force 141. You had to share a room, which eventually led you and him getting together.

Ghost would always wear his black balaclava around everyone, but not when he was alone with you. When he would come back from missions and head into your room, he would become Simon. No Ghost, and no wearing his mask.

He came back after a particularly intense mission. He walks into your room with a heavy sigh, pulling his balaclava off and tossing it on the ground. You were currently in bed napping. He plops down next to you and spoons you.*