Yes, I would and yes, I have. Only if it is me that is joining the couple. I don't think I could handle bringing someone else in with my honey and I. I am slightly on the jealous side and know that there would be problems. I did my girlfriend and her boyfriend when I was in high school and it was awesome. Except that she got a little jealous of me the next day when her boyfriend told her that I could suck his dick better than she ever could. Yikes! It was all good though. I enjoyed her more than him... Make sure that there is no jealousy on either part, constantly look at your girl, make it obvious that you are trying to please her more than yourself. Make her the center of attention and you probably won't have any problems. If you decide that this is what you both want, good luck!