This is why gays have fought for the right. They got tired of co-mingling their finances, buying a house together and then having one partner thrown out into the street with little more than the clothes on their back when one of them died and the parents (or nearest blood relative) inherited the house.

This is a lot less obvious in practice than it seems. Fair-weather 'partnership' isn't really rare. Unless it has been tested at times of adversity it is hard to predict how people would react. A piece of paper does not ensure that the relationship will be anything but of the fair-weather variety, with one ready to jump ship at first signs of bad times, it does give one an opportunity to reflect on the gravity of the promise and vows and the public nature of the promise gives it some air of barrier to dissolution.

Sounds to me you're describing the whole point of marriage as a contract, as it specifies the default set of conditions and requirements that are applied to both parties, and also the rights and obligations of both parties in case of a contract resolution and even breach of contract.

> This is why prenuptial agreements can sometimes be a touchy subject, since it breaks that assumption of complete trust.

Again, it sounds like you're describing the whole point of marriage as a contract, as its the original (and baseline) prenuptial agreement.