I am currently in an open, poly trio. I date a male and a female and we have the option of seeing other people sexually (safe sex, of course). While the female and I broke up for a while, she and I are now dating again. We have all been together in some form or fashion for over a year.
First of all, you need to know that polyamory is not polygamy. Polyamory means having multiple loves. Polygamy is the marriage of a man to more than one woman. Just a little terminology trivia.
Society tells us that the "right" thing to do is to settle down with one person, but the truth is love isn't like that. Love is infinite; there is no set amount that we have and if we use it up, we use it up. Because love is infinite, it's possible to love and be with more than person at once. Many people don't tap into this capacity, but it's possible, and there are a few people who are in touch with it and pursue multiple loves. Society also tells us it's wrong to be with multiple people sexually, just like it has told us it's wrong to be homosexual, but that's wrong, too. There is nothing wrong with expressing oneself sexually in a liberal manner. For these reasons, and many more, there is nothing morally wrong about polyamory and open relationships.
Being in a polyamorous relationship is one of the most rewarding and challenging things I have ever done. Throwing in three people's wants, needs and boundaries and trying to make them work is more difficult than just doing it in your typical two person relationship. There were times when both my female partner and I needed something and my male partner had to address one's needs before the other, and those times were hurtful. They will happen. Fights are more difficult too because more people are upset; you're trying to balance more people's satisfaction and complaints.
Jealousy and envy are big problems too. They can crop up out of nowhere and sour an experience the three of us are having. I can watch the two of them kiss, or he can watch she and I kiss, or she can watch he and I kiss and WHAM! Jealousy is there, or envy. It's hard to deal with, and it can cause a lot of fights, especially if you can't determine the cause. But once you start pinpointing jealousy it gets a little bit easier to cope with.
There are lots of challenges, but there are lots of rewards too. We are a family; we all support one another and care about each other. We take care of our own. And that's a very special, unique feeling to have. Most days it's worth all the challenges.
If you want to know more, feel free to
PM me. I'm always happy to talk to people curious about polyamory.