Did you choose to be in a Poly relationship or did it choose you? Who will choose your next relationship? Find strength in the fact that you took a risk most people wouldn't consider. That kind of courage (like a muscle) gets stronger the more you exercise it. Besides, only those who dare greatly ever achieve great things.
My wife and I had just ended things with our girlfriend. It was a tough decision, but it was best for everyone. There were some hurt feelings on all sides, but we all agree it probably saved our friendship. Sometimes good people just arenít good together. There is no doubt that we will all start over.
It's not that I don't think you're entitled to your pain. Love can feel bigger than the sky when things are good, and it can feel like the sky just fell on you when things fail. Your reservations about starting again suggest that you expect to be negatively influenced by this experience. That's not really fair to you or the next relationship, now is it? Try to remember that there are no "bad experiences"; just experiences. They are only "bad" if you didn't learn from them.
Now get up. Dust yourself off, and dare to love greatly.