The National Marriage Project, located at the University of Virginia, published a report called, The Date Night Opportunity: What Does Couple Time Tell Us About the Potential Value of Date Nights?

The authors of the report write that the social-science literature suggests at least five ways in which date nights may strengthen marriages.  

1) Communication - date nights give spouses an opportunity to discuss things that are important to them.

2) Novelty - date nights help couples engage in novel activites that break the routine and helps avoid taking the relationship for granted.

3) Eros - date nights allow spouses to engage in romantic activites with one another and increases their sexual satisfaction.

4) Commitment - date nights strengthen the commitment by fostering togetherness and signaling to others that the spouses take their relationship seriously.

5) De-stress - date nights allow spouses to enjoy time with one another and relieve the life stress they experience.

The authors of the report write in their conclusion: "The Date Night Opportunity finds that couples who devote time specifically to one another at least once a week are markedly more likely to enjoy high-quality relationships and lower divorce rates, compared to couples who do not devote much couple time to one another."

Find a copy of the report at: The National Marriage Project