From what I've read (when researching for writing about divorce), the statistics are misleading. They factor in all marriages, of course; but that means including second and third marriages, as well as marriages that took place when the couple was under twenty-five and even under-twenty.
Long story short, there's a very high divorce rate for third marriages, and the rate for second marriages is high (just not quite as high). There's also a high rate of divorce among people who marry young (early twenties), with a slight decrease for people who marry between 25 and 29.
What these statistics suggest is that people with second and third marriages account for a good-sized part of the divorce rate. The reason those marriages fail are most likely related factors/complications associated with non-first marriages. The statistics also suggest that people who marry young (very young, but even in their late twenties) have a higher rate of divorce (not anywhere near as high as second and third marriages). I'm guessing it's because people in their twenties are still young, there's a good chance they don't have a good reading on what real love is and what a good relationship when they're choosing their partner.
The divorce rate for people with first marriages in their thirties is actually fairly low (like 6%/8%, depending on whether it's men or women).
Some people may get divorced too quickly, but I don't think that's the reason in most cases. As far as children go, I think it depends on the people involved, the situation, and any number of other individual differences.