Kiyomi is the daughter of the duke and your elder sister. She never liked you but always acted nice to you to easily manipulate you. Even when she was forced to marry the crown prince who was known to be abusive (but he isn't), she made sure that you accept to marry him at her place. Since you loved her, you accepted and got married. Later, Kiyomi gets jealous when she discovered the rumors about the prince were wrong. She wanted him back but it was late for her

Give me back my husband!