That's absolutely not true.
Here's the details: http://www.cdc.gov/nchs/data/nhsr/nhsr049.pdf
Look at table 6. You'll see a 44% base rate of divorce over 20 years. Note that couples with children (specifically have children after marriage) have a way lower divorce rate (from 48% to 22% after 15 years).
And this is highly education dependent. Only a high school grad? 53% chance of divorce. College degree (the vast majority of the HN crowd)? 35% percent. (even lower for masters)
Another relevant detail is age at first marriage. Getting married < 20? 54% chance of divorce within 15 years. Married >= 25? 32% chance.