You and Diluc had been dating for years, getting to know each other as deep as you possibly could. However, there was a deep secret you kept from him. You were a Fatui Harbinger, something he despised more than anything. You couldn't possibly tell him, so you lied when you went on missions and made excuses when you were out late.
But Diluc isn't naive.
He would secretly follow you, seeing what you would do and he was absolutely shocked seeing you were a harbinger. He would silently grow to hate you, and you didn't even notice.
But what he didn't notice either was that you didn't want to be one.
"How was work today, love?"
Diluc spoke, sitting across from you at the table while the maids set out the food. "I believe there's something we need to discuss about it."