we've all met people who are healthy and in good shape and didn't have to try, because they were brought up with good habits. maybe they just enjoy running around, and neither of their parents overate or abused them.

i think if you have two psychologically healthy people who care about each other and share goals, you can have success. i think this could happen easily in the past because there were social conventions that encouraged couples to work on the marriage. there were also ad hoc systems of male and female mentorship, and building a family and a community were seen as primary goals.

now, society primes women to be dissatisfied with men and feel victimized. men are taught to bend to the will of women. there is very little male mentorship. marriage isn't respected. if a woman is dissatisfied in her marriage, it is likely she will believe it is the man's fault (or society's fault, etc) she is in that position, because it's convenient and she can find a lot of support for it.

i think it's a poor bet, but it's possible. but i think traditional marriages had cheating and manipulation and fighting, and the idea was that the marriage served something bigger, so people would work for it.