I want to stress how important it is to see polyamory as an approach or a mindset rather than a rigid relationship model or structure. Polyamory is very flexible in nature, and offers the ultimate freedom to partnerships, expression of sexuality and self. In fact, I find it of secondary importance how many people are involved in my relationships. I understand that many people choose (and prefer) to be with one person only, and that's perfectly fine! What I think is that not only everyone prefers a different relationship model, but also needs of any one person change throughout their lifespan. I know of a few exclussive and happy relationships, and I also have seen people marry in love, and then divorce a year later.
In my opinion, I think you can be polyamorous and still live with only one person. You can be polyamorous and live with three, four, or more! I think what defines polyamory is more about how you percieve and understand relationships in general, and what you expect from yourself and your partner(s). Each nonmonogoums relationship depends on unique arrangements and agreements between the partners involved. So for those of you who are confused about what polyamory is (at least to me): it is a way of thinking about certain aspects of life. It is a commitment to freedom and communication.
I found a definition in Wikipedia which I think is very well put: "Many polyamorists define fidelity not as sexual exclusivity, but as faithfulness to the promises and agreements made about a relationship. A secret sexual relationship that violates those accords would be seen as a breach of fidelity. Polyamorists generally base definitions of commitment on considerations other than sexual exclusivity, e.g. 'trust and honesty' or 'growing old together.'"
Do you think your partner belongs to you, and to you exclusively? Does it make you upset to see your partner with someone else? How do you experience jealousy, and how do you consider your feelings?
I believe a polyamorous person will answer these questions in a certain way, and a monogamous possessive person will answer in another way.
I think a big problem emerges when our feelings (what we feel is right) disagree with what we were taught to believe we are supposed to feel-let's say you are in an amazing monogamous relationship, and one day you feel emotions towards another person. In our society, we are told that it is not possible to love more than one person at a time, so this creates an immediate internal dilemma.
You will most probably be discouraged to talk about your feelings openly with your partner (or anyone else in fact) and deal with it either by cheating and lying to your current significant other, by straying and abandoning your current partner, or by blocking your new feelings and feeling angry and possibly frustrated towards your current partner as well as yourself.
Image credit: polyweekly.com