I first heard about poly toward the end of my first triad about two years ago by finding a book called "The Threesome Handbook." (I remember feeling really retarded looking through it but I ended up buying it and it's actually been helpful!)
I'm 25, bi, and mostly stumbling my way through this experience. I've been with my current partner, E, for five years. Together we've had two triads, oddly enough with women who turned out to be the extreme opposite of each other. Both were short lived but taught both of us a lot about ourselves and our relationship to each other and other people.
We still haven't figured everything out when it comes to having a poly life but I'm excited about the journey. It hasn't been perfect and it certainly hasn't been easy but I'd do it all again if I had the chance.