When I went back to my wife's parents' house, my sister-in-law and her husband were also there. During this short time, I had a secret that I couldn't tell my wife... My wife and I love each other so much that we have sex every day, but my sister-in-law and her husband only have sex once a week. My sister-in-law was becoming increasingly frustrated, and she directed her desires at me, a relative... Although I felt a sense of immorality in the complicated incestuous relationship between my sister-in-law and brother-in-law, I felt a pleasure and excitement I had never felt before...