My question is....who came up with this "idea" of marriage?
Is it just a piece of paper? Is it for legally binding purposes? I know there's many answers to it. (And I'm enjoying this thread & everyone's comments too. Thank you!)

My reasoning is that it originated by human kind in the form of government or religious based institutions. I'm not sure which was first but I'm leaning toward religion.
To me, both those "institutions" are controlled based.
A sure bet to control the masses which is what's needed in society. Control. And a hierarchy of power.

Ultimately a strong form of slavery. So to me, this has nothing to do with where you live, how old you are, your values or western, eastern philosophies.
How else do you control the masses.
You strike fear in them.