The Terminally-Ill Side-Character Inside of a Martial Arts Novel

I became the younger sister of the male protagonist in a martial arts novel. A terminally-ill side character, who was sold to the Demon Cult for the family’s sake. * * * “How come you don’t want anything from me?” He, who was to be my husband, would occasionally ask, as if he couldn’t understand. Whenever he asked, my answer remained the same. “Because there’s nothing I want.” However, despite my answers, he would gift me many things. He sent money to my family, bought me jewelry, and gifted me with the ivory and silk from the western lands. “Don’t you want anything more?” He asked again if I wanted something, and I still just shook my head. Normally, he would nod and turn away, but...