Disillusioned, I think you are failing to fully realize that people have free will. Yes, most "civilized" cultures encourage monogamy and often present it as the only option.... but we are not robots.
GREAT! Exactly! But this is where you don't "get it", that's the last piece of the puzzle:
When you are presented with one option, you become a robot, if you want it or not. Monogamy is not presented as a "possibility", one of many. It is presented as the "default". As YOU said it - THE ONLY OPTION.
That's what Hegemony is all about, when control is achieved through consensus, not force, when an opinion or an option becomes common knowledge which is accepted a priori.
Then the discussion automatically becomes to be "why are some people not monogamous?" rather than "are we monogamous?" Our frames of reference are hijacked by the Hegemonic ruling consciousness.
A couple I know just got married, partly so they could cut their medical payments by half. How many people get married so they can get a mortgage? For legal status?
How many times was I asked: "How long are you together? What?! 3 years / 4 years / 7 years / 9 years??? Why aren't you married!?!?!"
ANY BUSTARDS AROUND HERE? How do you feel like being called A BUSTARD?
There are so many unhappily married couples out there, who constantly fight, who rarely sleep together, who can't even remember that once they used to love each other... - yet they still stay together because of 1001 reasons - and that is considered NORMAL.
Then there is another couple, who is happy and deeply in love, but they have an open relationship or they swing together.... how would most people call them?
FREAKS FREAKS FREAKS !
Swingers, open relationships, poly = "fringe" "underground" "crazy" "sick" "a lifestyle".
But Marriage? = AN INSTITUTION !!!! It is the INSTITUTION of marriage, given to us by none other than almighty God himself!
Most people will not consider doing anything which isn't perceived as "normal" because, god forbid, "what would people say??"
Why won't you use your REAL NAMES? Why won't you use your REAL PHOTOS?
Do you understand in how many different and complex ways you are controlled and indoctrinated towards a certain POV? Cultural, social, legal, conceptual, lingual !! Language itself controls you, from within!
So, do you REALLY have free will? Or is your free will just an illusion?
Lets step back from confusing philosophical talk... I will give an example - you walk into a store. The sales person tells you: "Hi! You are free to choose to buy anything you like!" Then you walk around the store but the only thing they sell is bottles of Diet Pepsi. They are everywhere. Thousands of them. You walk around for hours, all you see is Pepsi Pepsi Pepsi. Finally, if you are lucky, you discover that in the back of the store there is a special shelf - most people miss it for a lifetime! The shelf has a sign that says "products for special people" and it has a bunch of warnings all around it - enough warnings to keep away most people. On that shelf you find Coca Cola, Sprite... and more variations of Diet Pepsi.
Free will ? I think not.
*** SIC SEMPER TYRANNIS! ON WITH THE REVOLUTION! LOVERS OF THE WORLD - UNITE ! ***
And with that - I have rest my case.
The defense rests, your honor.
(trying to be funny and dramatic, I hope some of you appreciate it)