Time Magazine's Healthland blog on the recent State of Our Unions: Marriage in America report "When Baby Makes Three":

The authors came up with five qualities that happily married parents share. Moms were more likely to be happy in marriage if they had, in order:

1. Sexual satisfaction
2. Commitment
3. Generosity to husband, including small acts of service like making coffee for him in the morning, expressing affection, and being willing to forgive
4. Good attitude toward raising kids (i.e., she wanted them)
5. Social support from family and friends

The top five predictors for happily wed dads were the same, except for No. 5, which was a shared "marital spirituality"; e.g., the couple says God is at the center of their marriage. Other characteristics of a content couple included having a similar faith and sharing the chores. (My personal favorite sentence in the report: "[W]omen are more likely to report that they are sexually satisfied when they report that they share housework with their husbands."