Their Lover (Child's Prey #5)
Barbara Sheridan

After the men share a scripted kiss in a music video, the trio's relationship takes an unusual turn. Old desires awaken within Kyoru, new fantasies in Sasao, and Ken is afraid his presence may jeopardize his friends' marriage.
Reluctantly, Ken leaves the couple's employ but when another frightening situation draws him back into their lives, Kyoru and Sasao will do all they can to hang on to their friend and convince him they're good for each another in every way imaginable.