With all the knowledge available now, I can say that I agree legal marriage should be avoided. Life-long LTRs might also need to be looked at closely, which would include never, ever commingle any funds.
I married the elusive unicorn. She was elusive because she has serious social issues (leans more towards being a recluse, slight OCD). Me being a late bloomer, mostly blue pill type personality, I was happy to have found someone, my first LTR girlfriend. The problem was that I masked issues of intimacy and her social problems by working many hours, being a day dreamer, etc.. For the first few years, this was OK. Finally I got feed up and told her our sex life, while there, was just too low key, to scheduled. It got better, and I went from happy to content. The last three or so years, it hasn't been all so great. She got to invested in her daily, weekly pattern. Didn't want to attend my family events unless they were in the evening. Would get all worried when her family had a noon gathering. She went, but didn't like it. She didn't want to try new things like rope courses, waterparks, etc.. Vacations are sometimes boring with her.
This almost caused me to have an affair. I didn't, but I now can see how easy it can be. Most of us are going to live way past forty. Most of us are going to have a fairly easy life when compared to not that far back in the past. We don't have to work hard for our food, wood, etc. to survive.
I think the change in humanity has changed how marriage and life-long partnerships should work. This also includes how a society will produce off-spring as well. The old Leave it to Beaver ways worked well for humans due to limited mobility, short lifespan, and strong beliefs in morals and values of the time. Sure, it wasn't as if everyone was some Holy Roller, but I do believe that many people were.
Then things changed, and so has society. Marriage as we know it isn't a wise investment. Even life-long LTRs are iffy until a human reaches their 50s-60s. There is just too much temptation in life, in my opinion. To many people to get to know, intimately, to experience life with. Sure there will always be heartbreak when a couple separates, but that is just how things will be in the future.
This book is a how-to guide on how to fix a marriage and make it seem as if people should get married, know there will be cheating, but lets just deal with it. Sick. How about we avoid marriage and this never becomes an issue. Of course that agenda isn't going to be pushed, because it will have a huge impact on society at large (and it already is in some aspects).