Is monogamy natural?

The Oxford dictionary definition of natural:

existing in nature; not made or caused by humans.

   I hear often that Monogamy isn't natural. Yeah. Right. Probably it's not. Because you are exerting so much effort to stay monogamous. Because everybody gets attracted to everybody else all the time.

   But is non monogamy natural ? Everybody is jealous and territorial when it comes to the person they really care about or want in their life. Almost every man and woman would prefer that certain fancies of the person they love are particular to them. (I am talking about a very clear majority here, not the exceptions such as people capable of polyamory).

 I don't know where this desire of having one person to yourself came from. As far as i know, nobody else knows that either. Maybe they tried it in another way in a time when history wasn't recorded and it didn't work. Regardless of its origin on the map of human society, jealousy seems to be a very innate emotion in people, even in the age when no indoctrination has influenced them yet.

It is evident in how a child throws a tantrum if his mother picks up another kid or gives him more attention. So, I strongly doubt that this emotion is merely a curse of the societal hierarchies we have created and the family systems we believe in, although they play a big role. Some societies managed to do away with the traditional concepts of love and two person marriages, and had practices such as collective upbringing of children of different fathers by the entire community. They surely had different ideas about love, life and family because of which they survived instead of descending into hot pools of vengeance and bloodshed. I don't know if jealousy never arose in those set ups or that they made their emotions obedient to the status quo. Such examples exist, but they are few. 

What we do know is that jealousy as an emotion, is as old as the mankind and you find proofs of it everywhere in history. Infact the classic divide between good and evil can be traced back to acts of jealousy in Abrahamic religions. Satan was an angel that turned evil when he felt that others were favored over him by God.

   Then surely, this jealousy is as 'natural' as the indiscriminate physical attraction people feel towards others while being in committed relationships. None is less natural than the other.

    I am not saying what is the right way to go about it and what is or what should be the future of jealousy. Maybe it is a higher point of evolution of human emotions when they do away with feelings like jealousy and maybe it is an ideal to aspire to, because in the end, it IS a negative experience for everyone involved.

   My only point is that as things stand, saying that monogamy is obsolete because everyone gets attracted to everybody, is not a valid enough argument because it is easily countered by the fact of you experiencing jealousy about sharing the person you love. You do want the things to be exclusive. You do want the experience of having one person to yourself.

So what do you do? It's so confusing. Both experiences feel legitimate. There seems to be no definite conclusion.

    The ones who find the strange and elusive specie such as 'the one' , say that they never want anything or anyone else ever again. 

   Rest, just kind of keep wondering , keep getting swayed, keep feeling guilty , keep feeling lonely inside and if they are lucky, they spend their life with someone they can at least cherish an attachment with. In the end, it doesn't sound like a bad deal to them usually.

 But only a few people in life have the gift of certainty about this situation.