My writing friend Carol Cassara, appearing on the web as The Middle-Aged Diva, recently turned her blog over to a polyamorist. You'll find the original post at that link, plus a number of questions and comments I posted in response.
I have many friends across the "believer's" spectrum, many of whom adhere to humanist, situational morals. I don't, at least all the time. I believe evil exists. I believe that people can do evil. I believe human evil is expressed as sin. I prefer not to sin, if you'll pardon the occasional white lie. I believe religious (not legal) marriage is a spiritual relationship between a man and a woman.
I will even confess to a measure of situational ethics, since I believe society has evolved in such a way that everyone should have the right to civil unions.
However, there is no way a person can explore this world by approaching every person he disagrees with in ethical matters and yelling "You're sinful." People are responsible for their own actions, the consequences of their actions. And their spirits.
Nevertheless, in this discussion, and even though it bears a negative connotation and may be an unfair generalization in the specific case, I feel people rationalize their choices. A polyamorist rationalizes his or her choice as an expression of love; I rationalize my fidelity to my wife as sanctified loyalty.
Every human being rationalizes daily, from deciding a preference for breakfast, choosing a bank to hold their mortgage, or, as in this case, interpreting marital vows. That means a polyamorist will justify personal choices, and in turn, point out that I am justifying my choice not to participate in such a lifestyle.
There's also a question of gender bias. I believe men and women also approach the place of sex in culture and in human relationships in a different category, and that in turn leads to a whole bed-full of questions about polyamory, at least from a male (my only perception) point of view. Who comes first in a polyamorous relationship? Where do loyalties lie? Why does a man or a woman think they are entitled to perfection in personal relationships? If polyamory, why not polygamy?
I think I know the answer to the final question. Liberal humanists will tell me that polygamy is male oppression of the female. Nevertheless, if polyamory is focused upon personal satisfaction, the ability to live freely in pursuit of one's desires so long as no other person is harmed, why should a polygamous relationship voluntarily entered into be any different? Or polyandry, for that matter?
However we justify (rationalize) these personal choices between two (or more!) people, unique to each situation, we still need to focus on how these relationships influence society. No doubt the growing movement for same-sex marriage will influence our culture in ways we don't now foresee. People pursue expansion of personal freedom, and societal norms are liberalized. But I doubt the choice of one partner, or multiple partners, will have as much influence as gender-selection abortion, eugenics through pre-natal manipulation, and genetic manipulation of embryos in laboratories, but it will change the way we perceive marriage and family.
To me, marriage is about love and commitment, and to a degree, sacrifice of ego to gain something greater than self-gratification.
However, the discussion did end up on Reddit, and there my point of view found little, if any, support. I didn't bother to participate, primarily because most of those in support of polyamory were intent on personal attacks (I realize I made myself a target, but ad hominem attacks are merely noise) and my marriage about which they know nothing.