Recently, a study in the July 2010 issue of PLoS Medicine revealed that "a higher level of social interaction can raise your chances of survival by 50 percent." (Article about it.)
The researchers in the study "analyzed data from about 150 previously published studies that tracked both social interaction and health over time (an average of seven and a half years)." Those people who had "better social integration were 50 percent more likely to live through the follow-up periods than more socially isolated people, regardless of health, age, or other factors."
One of the researchers also noted that "marital status - independent of marital quality - increased odds of survival by 33 percent."
So, "strong family relationships indirectly help to maintain physical health, too." (A fun bar chart accompanies this article that displays the difference in healthy habits and social integration.)
No matter how stressful life gets, my relationship with my husband brings me strength, hope and comfort. We also work hard together to create multiple social groups wherever we live (this isn't too difficult since we are Mormons). I'm not sure it will increase the longevity of my life or his, but it will surely increase the quality of my life - manifold - because my life has been absolutely wonderful with him so far.