A little more OT, but Revs point raises an interesting point about why humans, as an animal, are weird. Biologically, we as Rev says want to pass on our genes and have done with it, with some desire to protect that future gene investment, which given we are from similar stock to apes probably derived a troop structure.
But as we've advanced we've made that desire culturally unacceptable and for the vast majority straight up unfeasible.
IMO, we've no inherent desire to be monogamous (and few of us are, though many eventually do of course), but a strange twist of how we've made our society makes it something we wish to, and feel we should do. We've gone from a small troop seeking protection and guidance from a alpha parent, to having an absolutely enormous group where we don't really need protection, but as such also desire some structure to the family unit. You could argue that the genetic argument could extend to us now wanting to protect our future gene investment and thus that in turn leads to a desire for monogamy, to make sure our genes make it.
(That is riddled with flaws and holes but it's an interesting way to take a one night fandango thread to )