I am looking for a book i read about 10 years ago about a man who starts a relationship with his professorI think, the professor is gay and comfortable with it but the younger guy isn't. The professor goes on a voyage on a scientific research ship, arranges for the younger lover to join him. Meantime younger man meets the professor's sister, falls in love with her and decides he might not be gay after all. Struggling with his choice, he joins him on the ship as promised and becomes very resentful and leaves him on a deserted island. I can't remember how it ends and would love it if someone could remember author or the title of it..?
