I've been polyamorous since my teens (I'm 47). I've tried monogamy a few times, and I can do it without problems (I've never cheated), but I'm happier in ethically non-monogamous relationships.

Yes, polyamory can definitely work, just as monogamy can work. Whether or not it will work with any particular set of people at any given time is another thing altogether. It depends on the people and the situation. It depends on the relationship skills present and the will to use them, and so much more.

I've heard polyamory described as the graduate school of relationship styles, and it is that in some ways. You're balancing the needs of at least two (maybe more) relationships at one time, while you also need to take care of yourself properly in order to be ABLE to be a healthy partner to anyone. The factors present in a triad, quad, or moresome usually mean that all the little things that we just let slide in a couple usually come to the surface more quickly as points of focus. Your communication, negotiation, consensus building, and time-management skills WILL be tested, repeatedly.

Lest this sound like all work and now reward - you have that much more love in your life, that many more wonderful partners to rely upon, that much more sex, and so on. Metamours (your partners' other partners) can become a wonderful network of friends.

I highly recommend a book called More Than Two by Franklin Veaux and Eve Rickert that will be released shortly (I read a prerelease copy) . It contains all kinds of information about polyamory, how to do it well, and how to learn from the many ways other people have screwed up doing it. The information on communication skills would be well worth the price of the book all by itself.