Marriage provides more and better sex
Sex within marriage has an enduring and unifying quality.
The enjoyment of sex in marriage is described in the marriage service which says: "The gift of marriage brings husband and wife together in the delight and tenderness of sexual union.."
Author and theologian Adrian Thatcher writes in his book ‘A Guide to Christian marriage’:
“[The] difference between married and unmarried in the quality of the enjoyment of sex requires an explanation, and one is ready to hand. It lies in the old-fashioned virtues of love and commitment…. Married couples take time out to please their partners and satisfy them thoughtfully. Love and a concern for one’s partner shifts the focus away from the self in a sexual relationship toward the other person.”
In their influential book ‘The Case for Marriage, Why Married People are Happier, Healthier and Better Off Financially’, authors Linda Waite and Maggie Gallagher echo this idea:
“For both men and women, marriage….. facilitates the development and maintenance of an emotionally committed, long-term, exclusive union, which typically brings spectacular sexual rewards.”
Contrary to popular perception, an academic study (Money, Sex and Happiness: An Empirical Study) based on 16,000 American adults, found that married people have much more sex than other groups. The authors demonstrate that sexual activity is strongly and invariably correlated with happiness. So more sex may be one reason why marriage makes you happier.