For me it’s one of those situations where you are right about how society should operate. But practically there are many customs around marriage that are diffic

For me it’s one of those situations where you are right about how society should operate. But practically there are many customs around marriage that are difficult or impossible to recreate. For example, hospitals allow spouses in patients rooms and to make medical decisions. Even if you have medical power of attorney, it doesn’t change hospital policies to allow you to hold your dying spouse’s hand even when visitor hours are over. Hospitals should have better procedures to allow a single person specified beforehand. But not all do. And I never know where I or my spouse will get sick. Being married helps to “fix” what’s not possible in many countries, states, and places. Similarly with raising kids. There are countless customs where being a spouse makes an interaction at school or daycare or healthcare seamless, but being something else turns into really unpleasant situations. Of course it shouldn’t be and those institutions should change. I’ve found them getting better in the past 30 years, but still run into issues. I grew up reading Heinlein and thought the social contracts were cool and hope that the future makes this better. But right now, the best way to have a joint life with someone is to get married. Not to mention that there are massive tax benefits for raising children with the US tax brackets for married on one income. To be efficient with taxes, people with equal incomes should marry while one pauses their career to have tax benefits of married with one income. Then once they are ready for daycare or school, get divorced as there are substantial penalties for two equal earners being married.