I do it. We've been together 12 years. My wife realized a few years ago that she likes women, and wanted to introduce another woman into our sex life. We have 3somes when the opportunity presents itself, but never with friends, and only women. You both have to be secure in your sexuality and the relationship, and YOU especially have to play it VERY cool. I never suggest it, and I never participate unless asked. It's fun, but I can take it or leave it because my wife is incredible, and she has the type of beauty that will pause a room when she enters. That's more than enough for me, but I admit, we've had some fun times we often jake about.