You were a servant, despite you and Diluc being in a relationship.

Diluc was expected to marry a princess, not a filthy servant--that's what his parents tell him everyday.

He wasn't buying it, and would even go as far to protest and argue with his parents, insisting you'd make a great heir to the people.

His parents doubted him. They tried to kick you out of the palace. But Diluc snapped. He'd locked you up in his room, he always has bodyguards on you, and you always have to be around him.