Bisexuality Support Group
Bisexuality is a sexual orientation which refers to the aesthetic, romantic, and/or sexual attraction of individuals to other individuals of both their own and the opposite gender or sex. Most bisexuals are not equally attracted to men and women, and may even shift between states of finding either sex exclusively attractive over the course of time.
from talking to others (and i might be horribly off on this, but it's just my personal experience), 3-somes are actually a bit rarer than people think. and speaking as a male and seeing what happens to the relationships i've observed after they've done something like that, it tends to make the relationship a LOT more difficult. one partner (typically the guy) thinks that since his wife/gf has done a 3-some once, he is almost entitled to ask for one every time he gets the urge. and the other partner generally begins to feel unwanted as their spouse constantly wants an additional partner. i think it's just a difficult thing to really analyze, as every relationship is going to be a little bit different lol