The divorce rate is a little cooked. Those who suck at marriage are represented over and over. Those who are great only get included once each.

I always shudder when I hear a couple claim that they negotiate everything.

Negotiating is how we establish an exchange rate. If you have chickens to trade and I have oranges, negotiating the rate requires I talk down the quality of your chickens, and talk up the freshness and sweetness of my oranges; while you do the opposite.
That hardly sounds like a solid basis for a satisfying relationship.

The only workaround I've found is if I just give you 100% of my oranges, and you give me 100% of your chickens; then I can be openly appreciative of their lovely plumage and delicious eggs without hurting my supply.
That'll cost you all of your chickens though. Hope you like oranges.