One day, I witnessed my son's wife, Rio, cheating on me. It had been three years since I had been married to her son, and even her devoted housework became rough, and she often came home late. When I questioned Rio for her son's sake, she seemed to have regained consciousness and denied that she was cheating on her. When I got angry and found evidence of her infidelity from Rio's smartphone, I felt excited about her son's wife, which I hadn't been aware of until now.