According to many studies, people who have college degrees have more "successful" marriages. One of the most heavily cited studies was conducted by Pew Research Center's Social and Demographic Trends project which contained analysis of sixty years of Census data.
It claims the following:
-Spouses with college degrees have better dinner conversation
-Education/Intelligence is considered one of the top 5 most desirable qualities in a mate
-Coupes with degrees have a higher adjusted income (averaging around $76,652)
-Marriages in which the wife had only a high-school diploma, 38% dissolved in the first 10 years, compared with 16.5% in which the wife had a college degree or more
-They have greater job prospects/less employment instability, which reduce stress
-Families that raise their children with an eye toward the future -- a college degree -- are also families that tend to place values on other long-term commitments
The original article, with the above cited studies can be found here.