I am a 30 year old man. Recently, my wife and I visited her parents’ home. One night, I got a very strong sexual urge and to satisfy myself I went to the room where my wife was sleeping with her sister. I slipped under the blankets and had sex with my wife. However, later on I came to realise that it was not my wife at all, but rather her sister with whom I had had sex. She had neither protested nor revealed this to me through the act, as she was enjoying it, she told me. After that episode, my sister-in-law has forced me to have sex with her on many occasions and she is now threatening me that if I do not continue to satisfy her thus, she will tell my wife that I forced myself on her. Please tell me what I can do to resolve this situation. I love my wife deeply and do not want to lose her or see her hurt. What do you suggest I do?