He treats the heroine like a queen initially before his darker, more "sadistic and demanding" side takes over.
If you enjoy authors like Rina Kent or Bianca Cole , Aria Cole's world of possessive alpha men and the women who challenge them is a great place to dive in. Sadistic King by Aria Cole
Dark Desires and Secret Missions: A Deep Dive into Sadistic King by Aria Cole He treats the heroine like a queen initially