Sure.
Where being married is cheaper for health insurance is when you have kids, at least with employer group plans.
(Premiums for 2-party plans tend to be about, often exactly, double single plans. Family plans, for 3+, tend to be about 2.5 times. If your coparent isn't eligible on the same plan the marginal cost of each of the first two kids is higher.)
some company does provide medical insurance for "partners", but most probably don't, and that's a big headache.
It’s the children and fights over custody that cause the greatest drama and attorneys fees.
Custody, possession schedules, who gets to pick the school, who gets to make medical decisions for the kids, who decides if they ought get braces, who decides what extracurricular activities the kids are in and which parent has to take them, which parent can hold the kids passport and what counties can they take them to, geographical restrictions, morality clauses, right of first refusal, and on and on and on...
The vast majority of cases that got to jury trial are custody cases... rarely property issues.
(Indeed, in most states you aren’t even entitled to a jury trial on property issues.)
Consent was very important in the middle ages, and it's making a huge comeback in the 21st century.
(The monetary issues can be settled with standard contracts, but the sex part is what requires a special and distinct form of agreement.)
This 100%. Eleven years into our relationship, with now a 7 years old kid. We were raised in non-religious families and we are non-religious, so why get married? Why then bring the "religion of the state" in our lives? We don't need no public servant to officially declare us married. We don't need no state-endorsed paper. We don't need no more administrative burden.
A breakup would, indeed, be bad enough in itself to then add insult to injury by having lawyers on both sides competing to see which of them has the sharpest teeth while they'd be bleeding us dry.
Just screw that entire system.