I think divorce statistics are not related to age of pairing off, which if anything was younger farther in the past than it was even a generation or two ago. Divorce is simply not the social stigma that it used to be, and it's easier to get so it happens more now. Rather than working through their problems, people think it seems easier to just split up.
In very few cases these days. The majority of monies given out is for childcare, it is very difficult to have court ordered alimony for terms longer than 10 years even if the spouse was a stay-at-home parent for more than 10 years.
Of course you are correct that lowered social stigma associated with divorce is also important. This topic must be difficult to study over very long periods of time, because so many things are going on (changing age of first marriage, reduced social stigma associated with divorce, women's liberation, changing religiousity, etc. etc.).
