sex vs love

http://www.theglobeandmail.com/life/family-and-relationships/the-growing-appeal-of-sex-without-commitment/article1804708/

I came across this fascinating article on the 'growing appeal of sex without commitment'. It discussess the growing ascendancy of the notion of friends with benefits (FWB) beyond one's earlier years and well into professional life. I watched a bunch of the trailers that they suggested, but the funny thing was at the end of them it seems that the notion of love is deemed to be more meaningful, deep, and satisfying than the more casual sexual encounters - particulatly because it is love that draws them away from their initially FWB, playboyish lifestyles.

So why is society so obssessed with love, specifically the romantic, passionate love between two people? We are brought up to think that a vital and necessary part of life is to meet that special someone and then spend the rest of your days together - and that people who don't are somehow defective in some way. What drive this imperative? Is it something instinctually written into our DNA? Many would argue that this is not the case, that humans are not designed for monogamy, and that rather the primary biological directive of the male is to inseminate as many women as possible and the primary biological directive of the female is to be able to raise and protect her offspring. If monogamy is not evolutionary, then perhaps religion is the culprit, with a litany of mores on proper sexual practice (adultery, premarital sex, etc... are generally big no-nos), but even then I believe that polygamy is not uncommon in the Bible and the Qu'ran. So society then? Perhaps monogamy was designed as a means of preserving societal stability, so that kids would have two guaranteed parents to grow up with to take care of their wants and needs. But now, does society still need the institution of monogamy to stain intact?

Could you envision a world where we formed deep and close relationships with a network of friends, but there was not one only one person that sex was shared with (somewhat like the FWB notion put forth by the globeandmail)? Or perhaps one in which polygamy was accepted, rather than despised? A little strange, but I have to wonder, in something like 'what sort of relationships are the best', is there really any absolute right or wrong answers, or do we merely become creatures of culture and habit?