Most of the posters on this thread are pro-marriage, so I am going to provide an alternate point of view.
The main consideration of marriage that people overlook is that it is a LEGAL CONTRACT. Furthermore, it is the only LEGAL CONTRACT that can be broken by one party. Before getting married, please consult a lawyer familiar with property law in your state.
In my opinion, everyone considering marriage should read "The Case Against Marriage"
(https://www.amazon.com/Case-Against-Marriage-Really-Getting/dp/6056321533/ref=sr_1_1?ie=UTF8&qid=1467905693&sr=8-1&keywords=case+against+marriage)
and then think long and hard about how their marriage will be different.
When I was growing up I never saw any happily married couples.
As an adult I still do not see any happily married couples.
All of you happily married couples posting on this thread - where are you? Why don't I ever run into you?
We exist, promise.
I didn't read the book you linked to, but I read the Amazon summary, and it summarizes a lot of why my wife and I *did* choose to get married. For example:
Behind the romantic language, marriage is primarily a financial agreement merging the assets and liabilities of two individuals into a single corporate entity
Exactly. When we decided to have kids, and buy a house together, we made a plot of how we envisioned our finances (formerly entirely separate) changing over time, and decided that an arrangement that resulted in a complete share over time made the most sense. After all - we we starting to make huge life decisions jointly. Where to buy a house, where to live. We're both professors, but in different fields, so having a family immediately makes our job situation substantially more complicated were we ever to want to move to different universities.
Note also that it's more than just finances. Handing someone a durable power of attorney for financial, medicial, and nearly all other decision-making is a terrifying thing. But it's also pretty useful and important, again, particularly when you have kids. And the financial merging doesn't stop there -- we have additional contracts establishing trusts/etc., in the event that we die when our child(ren) are still minors, and so on.
I have friends who've done all of this without marriage - they're equally happy and healthy. They did pay more to the lawyers to set up the individual documents for these things, but they probably came out ahead when you look at the average cost of a wedding. :) But the financial entanglement is fairly similar when the sharing goals are similar.
Healthy relationships need clear boundaries, and marriage erases too many of them at once.
I couldn't agree more with the first part of this. The second -- I think it depends how you're going in to the marriage. First of all, the biggest boundaries people need likely aren't financial. Boundaries, the respect they imply, and autonomy ("this is my shit, please don't put your nose in it") are vital in all aspects of a relationship, and they're likely to be an ongoing discussion throughout many marriages. So, I'd translate this as: Don't get married until you and your prospective spouse have established healthy boundaries already!
One can maintain financial boundaries, of sorts, in marriages by choosing how you allocate and spend your money, and how you do that is independent of what the legal system says happens if you split. We chose a "joint funds, we each get $500/month of spending cash" approach, and figured that bigger purchases were probably worth talking about together. But what one spouse does with their allowance is entirely theirs, with no judgement allowed. There are many different answers to this problem. It's also noteworthy that this is one of the ways in which higher income reduces marriage-related stress: You can, as long as you and your spouse are generally agreed on your long-term financial goals and philosophy, just throw some money at the problem. When money's seriously tight, you don't have that liberty, and you have more friction.
The socioeconomic factors that lead to lower divorce rates tend to cluster -- my wife and I are both Ph.D.s, we hang out with a lot of people with substantial postsecondary education. As a consequence of that, our social group tends to have married later than average, and earn above average, all of which correlate with lower divorce rates. Many of our friends are happily married and/or life partnered.
It's quite possible. It takes a boatload of work. Our (pre-marriage) couples therapy bills were large for a year as we figured out how to communicate, and establish healthy patterns that worked for us.
footnote to add: Before the facepunches start flying about the extravagant "spending cash", what's mostly happened with that is that our individual savings accounts started getting larger and larger, and then we decided to renovate the house, and we drew down from both of them. It was probably too much of an allocation, but it turns out to not matter much.