Polyamory vs monogamy
An age-old question: Are people naturally polyamorous or naturally monogamous?
An age-old answer: neither. I don't think there is an ideal objective type of relationship in humans, the reason being the good old mystery of "free will", whatever you think about it; the concept itself is certainly different in terms of freedom and conscious choice in relation to many other species.
However, once we as a species have managed to influence and control to some degree the evolutionary and mating rules that would work in nature, human beings find themselves in the strange and surprising position of not knowing what they are made for, or if they are made for anything at all.
Personally, I am in a polyamorous relationship, though we have not yet fully consumed the meaning of the term. I have also been in monogamous relationships and in my personal experience every relationship has its own set of rules and compatibilities that define it as poly or mono.