I'm not completely certain what polyamorous is. If it means sleeping with a man and a woman at the same time, that isn't for me. I think I'm capable of loving more than one woman at the same time. I also think most humans are naturally the same way, that is, can love many of the opposite sex.
I have no idea how monogamy became so popular and so established in society and history. It is equated with morality, loyalty, doing the right thing, being Biblical, being correct, with true love as opposed to being untrue, and all that is good about relationships. And actually none of that is necessarily true. Even the ancient Hebrews took more than one spouse.
I suppose all of this is very nice but doesn't take social realities into consideration? I've lived with my wife for 17 years now, and we're both nearing sixty. I don't have any illusions about finding someone else to love if I leave her. Women are sweet to old men, but treat us like their fathers. I suppose it must be absurd that an old man should want to act like a young man, try to - I don't know. Follow my heart, I guess.