Childhood sweethearts separating in their late 30's

I've seen a rash of this lately, many of our friends married their first loves from school/college & are now going through marriage difficulties as they near their 40's.
I suppose never have even slept with someone else would make anyone curious as the clock ticks on.
Better to shag everything that moves while you can then settle down in your early 30's.
Couple who came together this way seem to be stronger from what I can see.

All this is my own opinion & anecdotal, has anyone else spotted a similar trend ?.