It has been three years since I married my wife. Back then, my income was stable, so I had no hesitation in letting her become a full-time housewife. However, we couldn't seem to have children, and she spent each day with nothing to do. By chance, she discovered a job as an "adult private tutor." Having worked as a cram school teacher before marriage, she decided to give it a try. Normally, tutors visit the student's home, but at my wife's request—since she didn't want her grandson to see her studying—we arranged for the lessons to take place at our house. The student was a kind, friendly older man who appeared to be past retirement age. Polite, humble, and diligently studying, his attitude made my wife start feeling a sense of purpose in her work. But one day, I witnessed an unbelievable scene. The man was as courteous, humble, and serious as ever—but he was naked, passionately embracing my wife...