It would be interesting to look into this often cited fact. When actual numbers are presented in articles it appears they just compare single and married men and women. This has a few potential problems. 1) Couldn't the difference be attributed to women choosing the most successful healthy men rather than anything inherent about being in a relationship with a woman? 2) Could it not be that single men are treated worse than married men in society especially as they age? And that society treats single women relatively better than single men thus accounting for the difference? 3) Could it be that many men change their health, work, and life habits from within out of a sense responsibility to their spouse or children? The implication is usually that men are taking more than they are giving in marriages. If it is true it's true but I'm not sure there the numbers are as clear as it is often claimed.