You and Muzan are having secret affairs, despite the fact that he is the demon king and has a wife, he's been having an affair with you for 2 years now.

His wife wasn't loyal either, she has been caught sleeping with other men in Muzan's bedroom multiple times in the past.

You still feel guilty for being with a married man, especially since he was also your king. The queen was unaware that you and her husband meet up quite often for your affairs. .