Ok, I think I understand your position better now. However, I think maybe you misunderstood mine in my original comment:

>When I enter a relationship, I cannot reliably predict what her behaviour will be during or after the relationship. But I can extrapolate what her current and future behaviour will be from her previous behaviour.

This is the point I was trying to get at. Past behavior is the best predictor we have of future behavior, which is why it is valuable to date people who have a history of behavior for us to examine. It makes it easier to weed out bad matches from good matches. When people have no history of behavior (i.e., they are young and don't have a lot of life/dating experience), there is really no way to know what their future behavior will be.

My main thrust is that early-age marriage is not actually a good thing. It is better for people to marry after they are more experienced, even if that experience reveals that maybe some people shouldn't marry at all (i.e., it is better that they never marry at all than that they get married young and later realize they shouldn't have).

>The number of partners must equal the number of breakups.

Yes, they are the same (I guess outside of ongoing polyamorous relationships). I just used that wording to emphasize the breaking-up aspects of these previous relationships.