Does anyone have any experience with them/have opinions on them? Just curious, I've never been in one.
Whenever I think about it, a relationship between three people sounds kinda odd- one person would be left out of makeout sessions, and it'd be kinda weird to give heart to hearts to two people at the same time. Not to mention finding a third person the two initial people both love. But I've always thought it would be interesting to sort of have a couple relationship- like, there are two couples, and each couple constitutes one 'boyfriend unit' of the relationship. So the two couples go out on dates, have sex (with all four people usually present, unless otherwise is allowed), etc, but you still have the two base couples to work off of.
At the very least, if someone wanted a group relationship, it would seem that an even number of people would be optimal.