My position is that the state has no place in private contracts, and that a marriage is a private contract.
My concern is that the nation produce laws for individuals and policy for families and this may further reduce the policy bias toward the family as a unit of production and reproduction, and increasingly toward the consumption (hedonism) of individuals – dysgenia.
A marriage creates a corporation in which shareholders pool assets, and it conveys limited power of attorney, to both (or more) shareholders to act on behalf of the other. If prenuptial agreements are adhered to rigidly, and there is no child support or spousal support then I am happy with it.
So my suggestion is to take the Alabama strategy and remove the state from marriage agreements, and let people engage in whatever relations they want.
So I am against state marriage en toto, and fully supportive of any voluntary contract that people wish to enter into. I would be comfortable with polygamy/polyamory evolving. But when I say I believe these things, it’s in the context of freedom of association and disassociation. So if you don’t want to serve polygamists, you don’t have to.