Among the reasons given by the Times for the decline in divorces are later marriages, birth control, and a higher rate of marrying for love as opposed to reasons like monetary gain or housekeeping skills.
Unfortunately, though, it's not all good news: Class is a clear dictator of how successful marriages are. Whereas the decline in divorce is mainly concentrated among couples with college degrees, the divorce rates are just as high as they were decades ago among couples with less education (who tend to be poorer).
As with many aspects of American life, things are sunnier on the wealthier side. But we're glad to see that love is on the rise, which means more children will grow up benefiting from the stability of their parents' marriage. Maybe, if successful marriages feel more like the norm at some point, children will be more optimistic about their future relationships — which, in turn, would lead to better relationships.