Help em find this manhwa

Guys im literally about to lose my shit.

So it’s a manhwa about a girl who got reincarnated as the villainess I think who imprisons the male lead at the start of the novel.
She had white hair and purple pinkish eyes, she always wore a mask meeting said male lead and the villainess before she reincarnated would leave him in a dark house and feed him some drug or something but she was giving him books and stuff just not affection
And when he finally escaped, as she expected, he came to be the emperor. He has black hair and gray eyes. And at a party he instantly recognized her and announced to be married to her. She’s a daughter of a duke I think and her father didn’t like that and so did she but he’s a crazy emperor so yeah.
He’s obsessed with her now, also locked her in a dark room and that’s as far as I can remember HELP