You mean like in Utopia?
Here in the real world, unfortunately, gov. does have a role to play in marriage contracts, ie, property rights, child custody, pension & benefit considerations etc.
By preferring a dream world to the messy realities libertarians provide ammunition to those people determined to undermine society's moral foundations.
Oh, I forgot, there are no morals above man's own wishes & desires, and as long as I don't interfere w/ you, you won't interfere w/ me.
What a beautiful world that would be. Maybe in the next world, but then there is no next world. hmmmm...a cunundrum.
I do not intend to interfere with you. You don't intend to interfere with me, do you....regardless of your understanding of what is moral?