Is it normal for a wife to get satisfaction with husband permission?

Even though I have sex regularly with my wife, I am not able to satisfy her. I knew this before I married her. She is into bondage and torture sex. It is the only way she can get off. I have given my permission for her to have any type of sex she needs with a couple I met in college, through a human sexuality class. I can fo watch them anytime I want, and have on occasion. My parents found out and think I am crazy. I was always taught a man was to satisfy his wife. So I do, just not myself. Am I normal giving her permission for satisfaction elsewhere, or am I crazy like my parents say. I am 30 and she is 22. We have been happily married for three years. When her car was in the shop, I even took her to them. Her car was in the shop for almost three weeks. One time I even watched for a while and have been asked to join them many times.