On topic: I think it depends on whether both parties were Mustachian when they married, or whether Mustachianism is a subsequent discovery, along with the degree of change. If you're both Mustachian when you marry, I'd think the chance of divorce is less likely, because not only do you have similar life goals, you've learned to talk about it. OTOH, if you're both happily treadmilling along in commercial hedonism, and one party has a come-to-Pete moment, well, that's like any other major change in a partner and can put a huge stress on the marriage. I'd think that would be similar to, say, both parties belonging to the same go-to-church-on-Christmas-and-Easter church when they marry, but one down the road converts to a super-fundamentalist religion. Some couples will navigate a change of that magnitude, while many others will not.
Divorce: I think most would agree that the best environment for kids is to have two mentally-healthy parents in a loving, supportive relationship. The problem is, if you don't have a good relationship at the heart of it all, you're already outside of that "best environment." At that point, the question becomes which is the best of the poor options -- tough it out, or split? I suspect the answer to that is dependent almost entirely on the two parents involved.
In many cases, divorce is bad for the kids because they usually live with mom, and mom usually makes a lot less than dad. Success in school is highly correlated with socioeconomic status, so if the kids' status drops, and now mom's working all the time to make ends meet and can't be as involved in their lives, the kids likely won't do as well in school. OTOH, what's the value of modeling a healthy relationship? You can measure things like changes in SES and grades, so it's easy to point to that and say, see, divorce is bad! But you can't measure all of the qualities and characteristics that really matter for long-term health and happiness.
FWIW, I'm one of those who thank God that my parents divorced. They married WAY too young and never should have in the first place. No, it wasn't easy in a lot of ways -- we were on Food Stamps for a while, I had Issues with my dad for years, etc. And yet I cannot imagine the stress I'd have faced every single day if they'd stayed married for my sake. Most importantly, my mom met my stepdad and married him when I was 9, and I got an up-close-and-personal view of a very, very healthy relationship that lasted until he died a few years back. When I met now-DH, my first thought was how much he was like my stepdad in the way he treated people (me, his grandma, the waitstaff, etc.).* But my stepdad taught me the kind of characteristics that made a good man and a good husband and provided a daily example of how I should expect to be treated by anyone I was close to. My life would have been infinitely poorer if he had not been a part of it.
*Turns out I got that one wrong in several ways. ;-) But we've navigated that, and it's been 27 years this year.
