Ok... time to say something blunt!
Let's look at a typical marriage (even though there really isn't one). Both husband and wife are probably wage earners, with a 90% chance (yes, it's been measured) that the man makes more than the woman.
In most cases, the husband is going to appreciate in value at a rate faster than women due to a lot of reasons -- some are wrong such as gender bias. Other reasons are valid, such as a woman taking time off and/or retiring to have and raise children. At any rate, a husband's career trajectory is often more lucrative than the wife's.
Here's where I get to be a sexist pig. One of a man's top assets going into the marriage, his earning power, will appreciate over time. One of a woman's top assets, her appearance and youthful energy, will depreciate over time. You see a fair number of 60 year old males with 35 year old women, but how often do you see the reverse?
Marriage is a way for women to "sell high". They capitalize on their appearance and youth, and bind the soon-to-appreciate male into what looks a lot like an income sharing plan. Even if the marriage blows-up, the husband has to continue to share income for some time in the form of alimoney.
So why do men knowingly walk into this even though they are buying at the market's "peak"? Society trains us that you're supposed to have 2.4 kids, a white picket fence, etc. etc. That's why you see a lot of "enlightened" males who have had their children and would never walk into a marriage again. Even if they had a 10 or 20 year differential on their next spouse, they still know they are buying at the market's peak.
I still think there has to be a better way... the idea of traditional marriage has run its course in my opinion. Its just frustrating because I don't have a better answer yet
And yes ladies... I know there are exceptions. But in all fairness about 95%+ of all alimoney cases go the same direction.