Isn't this data very skewed by the fact that not believing in cohabitation and not believing in divorce are highly correlated? This group includes lots of marriages that I wouldn't consider good outcomes even though they don't end in divorce.
> The most salient finding from this analysis is that women whose intimate premarital relationships are limited to their husbands—either premarital sex alone or premarital cohabitation—do not experience an increased risk of divorce. It is only women who have more than one intimate premarital relationship who have an elevated risk of marital disruption.
As far as I can see this suggests that believing in cohabitation is not a strong factor when it comes to divorce.
As I see the data in those green bars (the chart in your linked article), the chance of your marriage surviving ten years falls with each non-marital sexual partner you had before marriage in the way you might expect if your current partner had to go on competing with all your previous partners simultaneously. If she's the only one, she's the best. If she's one of two, the chance of her remaining the best is 1/2. If one of three, only 1/3 chance that she goes on seeming like the best of the lot, etc. (And substitute "he" where appropriate and note that the same calculus is being applied to YOU, too.)
Of course, maybe the marriage survival doesn't require being the best but just >= the past average or some other variation, but that still leaves a curve dropping in a sort of 1/n Zipf Law descent into too-bad-for-you-ness where the competition with the "ex"es never ends. Yikes.
> the marriage being very successful
> I haven't quite figured out why that is
It is not about software engineers, it is a general correlation to the "numbers" of pre-marital dates.
The lower the number of partners before marriage, the more likely is the marriage to succeed:
> http://socialpathology.blogspot.com/2010/09/sexual-partner-d...