A slightly different take....
http://www.usatoday.com/news/religio...ristians_N.htm
"But some scholars and family activists are questioning the oft-cited statistics, saying Christians who attend church regularly are more likely to remain wed.
"It's a useful myth," said Bradley Wright, a University of Connecticut sociologist.."
"Wright combed through the General Social Survey, a vast demographic study conducted by the National Opinion Research Center at the
University of Chicago, and found that Christians, like adherents of other religions, have a divorce rate of about 42%. The rate among religiously unaffiliated Americans is 50%.
When Wright examined the statistics on evangelicals, he found worship attendance has a big influence on the numbers. Six in 10 evangelicals who never attend had been divorced or separated, compared to just 38% of weekly attendees."
"David Kinnaman, Barna's president, said the statistical differences reflect varied approaches, with Wright looking more at attendance and his research firm dwelling on theological commitments."
There are many factors at play (economics, marriage rates, age etc.) but I'll stand by my observation that on average, families that actually attend church instead of identifying themselves as christian without participating have lower divorce rates.