Last year, when I was acquainting my DS #2's first grade teacher with our personal circumstances, she told me that he would not be alone for very long-- that my kids would see a wave of divorces as they got older; XWH and I just got divorced on the earlier end.
I don't know if people deliberately wait unless you mean wait until the kids are graduated from high school and out of the house-- then yes, I think that some do opt to wait until that point. I don't have any statistics about the average age of people who divorce (or how old their kids typically are), but when I was a kid, I don't think I knew anyone whose parents were divorced when I was in elementary school. By the time I got to high school, I knew several, had friends from blended families, etc.
ETA: Your story about your friend is really sad, but it also illustrates how we can look at other families/marriages and think that they have it made, but we really don't know what goes on behind closed doors. I know that I romanticize other people and their relationships way too much. I'm sure that many people have been shocked to learn about my divorce as well since I'm sure that I also appeared to "have it all."
[This message edited by tryingagain74 at 5:31 PM, September 9th (Monday)]