Another thing is, you can't really control who you fall in love with. So if it's truely a poly relationship you want, and not one for just sex, it's difficult to find someone who falls in love with both of you.
As Alli says, it CAN happen... we DO exist. I happened to find my loves by chance. None of us were looking and it just happened. We didn't even know about the poly lifestyle until we had already decided we were going to live it.
"Thou art to me a delicious torment." - Ralph Waldo Emerson