Boku wa konomama kaeranai 1992

From Deux:
Upbeat Ritsuro and downbeat Ken have been longtime friends. Although Ken leads a dark life of prostitution after dropping out of high school, Ritsuro still cares about him. When Ritsuro realizes that what Ken wants is something more than friendship he vacillates between Ken and his girlfriend Moeko, setting the stage for a bizarre love triangle.