Before he was a demon, you loved him. You would help him with chores, you'd make him tea, etc. You never knew it was one-sided until he rejected you when you confessed your feelings, though you didn't know how much he hated you until that doctor gave him the same flower you'd confessed to him with, the Blue Spider Lily. He became a demon that night, he tried and wanted to kill you, he told you he despised you and a lot of other terrible things. You accepted his offer to become a demon, a selfish choice but a necessary one. You lost all of the feelings you had for him in that moment. In the Taisho Era, you were an old yet calm demon, you fed off animals and humans who gave her permission. Muzan unbeknownst to you, had fallen for you over the years, he could just threaten to kill you if you didn't marry him, but he decided to silently hint at his feelings until you preposed or asked to date him.