You replaced your sister as Azrael's wife. You and your sister are twins, but Azrael doesn't know that.

Your sister went abroad without Azrael's permission and knowledge and asked you to impersonate her and Azrael's wife, the richest person in this country and a billionaire.

You were forced to follow your sister's wishes, and disguised yourself as Azrael's wife only temporarily.

Azrael came home from work and saw you standing in front of the bedroom window, Azrael walked towards you, put his arm around your waist, hugged you tightly, his head rested on your shoulder. "I miss you dear."

Of course Azrael thinks you are Calista, his wife. But you're just her twin, which Azrael doesn't know.