Small big rant here: TL:DR - this discussion has gotten short-sighted and petty.
There was a comment on men being "blind-sided" by wives wanting out - I took a small sample (n=2) which indicated that women often are very upfront about issues in their relationships, the men pooh-pooh the concerns, and then are surprised when the women leave. "Everything was fine, what happened?" Well, everything was not fine, they didn't listen, they didn't change behaviours, and the obvious happened.
As I said, my n=2, this won't always apply.
Also, historically women had no recourse in unhappy marriages, once they had more financial resources and legal rights they were able to contemplate going it on their own. What is the saying? Better a cottage where happiness lives than a palace without? Lots of women are choosing the cottages. Society discourages divorce in an agricultural society, because a farm needs a minimum of a couple and their children to be economically viable. The nobility/wealthy could always get divorces/annulments.
Re age - those of us who are "older" have lived through societal changes which may give us a bit more perspective. We have lived thorough "Divorce is a four letter word and whispered about" to the advent of modern birth control to high divorce rates. Of course every generation has some hard truths it has to learn on its own. Have fun, Millennials, you are not facing anything harder than we went through in the late 60's and early 70's with the sexual revolution. It's not any easier though, society has not totally adjusted to that one yet. Go read divorce law from the 50's and see if you like it any more, those of you who are complaining about present-day legislation. Wives who HAD to leave the work force when they got married (yes, that was standard, happened to my mother) got alimony (for them,not the children) all their lives, because they could not support themselves.
Also, remember during this discussion that it may well be very country specific - the US is not Canada is not western Europe is not Scandinavia is not etc. etc. Living together and having children is going to be a very different situation in two culturally different regions.
I am reading "Climate Wars" at the moment. I seriously think (and have always thought, for other reasons) our planet would be better off if we cut down (that is a planet-wide we) on the number of children, had them later to lengthen generation time, and had more of us refrain from having them at all. In Europe in the Middle Ages, many men and women did not have children (they were monks and nuns), most married late (I read once that average age of marriage for women then was 26), men married later (not until they could support a wife either through an established farm or a trade) and had other cultural practices to keep the birth rate down. It is pioneer societies (with lots of new land to be settled) that encourage young marriages and lots of children (i.e. the Americas once Europeans arrived). And from a population biology perspective, having men who are not interested in their children father children is anti-survival from a species viewpoint. So guys ( and girls), if you don't want kids, don't have them, and your genes can get left out of the gene pool. Its better for the species/kids to have parents who want them. And for the first time in human history, we can do this without too much difficulty (i.e. having to join a monastic order, or live with massive child mortality rates).
One more point - having children when a woman is in her 30's increases the risk of chromosomal abnormalities, and health issues for the mother. Sure you can know ahead of time, but having to decide whether or not to abort because of a serious problem is heart-breaking. This is why women have the "Ticking biological clock". What is less well known is that as men age they are also more likely to father children with chromosomal abnormalities. So, men also have a ticking clock, they just don't know it and don't have it affecting their decisions. These days, I believe, fertility issues are about 1/3 her, 1/3 him, and 1/3 them. Of course the men never believe it could have anything to do with them until the doctor tells them, society is so used to assuming fertility issues are "her" issues. So they put off marriage and parenthood, not considering the long-term implications.
Rant over.