He is Catlin Aragon’s stress reliever. Her weekly indulgence. Her respite from hectic, toxic life.
She pays good money to have him in her bed, sure, but he lets her. It is the only way at this point that he can have her.
Because she is the only part of his sordid life that made him forget, made him something that approached happiness. Even though it is a professional relationship, theirs is the only thing in his entire sorry life that isn’t totally screwed up.