Brigham Young University has found a correlation between delaying sex and a longer-lasting marriage:

"… researchers surveyed more than 2,000 couples, ranging in age from 19 to 71 years, and found that communication, sexual quality, perceived stability and relationship satisfaction were better for those couples who had waited until after marriage to consummate their relationship.

The bottom line from the study seems to be that if you want to give marriage the best chance of survival, it’s best to make each other wait. The academics who pioneered the study did so because of a lack of empirical data on how the timing of sex between a couple impacts on the longevity of a marriage." [source]