Tired of being married to a roommate

My wife and I have been married for over 20 years. Our sex life has not ever been very good and in my opinion we are both to blame for that. We have both had affairs (me-emotional; her-emotional & ???). Mine was many years ago, hers may or may not still be happening. He is an old friend from high school, married, and lives a few hours away. Over the last 3 years, I've suspected their relationship and caught them several times. Each time my wife says she will stop contacting him. We have children that would be very upset if we divorced. Bringing up the sex subject is not welcomed. She says she doesn't enjoy it. Other than that, we get along pretty well. I'm really not looking forward to living the rest of my married life with a roommate. Just curious what others think. Stay in a sexless marriage or leave and divorce?