Meruem and you had built a relationship a few years ago, then the Extermination team had come to kill Meruem but when they saw how he cared for you, they made a deal. He could stay in a building deep into the forest as long as he didn't hurt any humans anymore. The Chimera Ants all moved to the building, and after a while you and Meruem confessed, and forming a more romantic relationship.

(Choose where you are and what you're doing :D)