Forbidden Desire: The Vampire CEO's Servant

Echo was forced by her adoptive parents to marry Nikola, the founder of the Venture Group, as she was merely a "blood bag" for her sister's transfusions, and Nikola was already a "old man." After the marriage, Echo was shocked to find that Nikola was actually young and kind, with the sole exception of not allowing her to touch the coffin placed in his bedroom.