I have often heard this statistic quoted from pulpits and talk shows, but the truth is actually much more interesting than this fiction.  For specific details refer to this article and its references.  Here is a summary of what it says…

• Active participants in faith are far less likely to divorce than secular couples.
• Passive or marginal participants in faith are far more likely to divorce than secular couples.

This is not really surprising given that throughout the Bible, the greatest judgement falls consistently on those whose faith is only superficial.  By contrast, those who recognize their weakness are embraced by Jesus.

These people come near to me with their mouth and honor me with their lips, but their hearts are far from me.  Their worship of me is made up only of rules taught by men.1

Woe to you, teachers of the law and Pharisees, you hypocrites! You are like whitewashed tombs, which look beautiful on the outside but on the inside are full of dead men’s bones and everything unclean.2

You were running a good race. Who cut in on you and kept you from obeying the truth?… The one who is throwing you into confusion will pay the penalty, whoever he may be…  As for those agitators, I wish they would go the whole way and emasculate themselves!3

I know your deeds, that you are neither cold nor hot. I wish you were either one or the other! So, because you are lukewarm—neither hot nor cold—I am about to spit you out of my mouth.4