Hi Ananda,
"No one could be fair to more than one lover."
I'm not sure that you can know that, which is the whole point in saying that it is a lifestyle choice. You can of course choose monogamy for yourself. But by telling another that if they choose polygamy or something other than monogamy they will "not be able to be fair to more than one lover" *IS* (at least in my opinion) forcing your opinion on another.
I realize that having more than one romantic partner is going to have it's own set of challenges, but that again is the "lifestyle choice." Hell, there are entire sects of religions (like fundamentalist Mormons for example) that have polygamy as part of their defining characteristics (
http://en.wikipedia.org/wiki/Polygamy)... and many of those families live happy, well adjusted lives not just as lovers but as parents.
So, I respect your choice to practice monogamy but I think you should also respect other people's choices to practice whatever kind of relationship they resonate with without telling them that there is zero chance for a happy successful relationship unless their relationship has the same format yours does.
Love,
Carson