This study also got a lot of press:
"The greater the age difference, the lower the wife's life expectancy," Sven Drefahl of the Max Planck Institute for Demographic Research in Germany, said. "The best choice for a woman is to marry a man of exactly the same age."The explanations are ridiculous and unsupported. A woman who marries an older man has probably sized him up as being particularly healthy, and that is why he lives longer.
Drefahl believed that having a relationship with a younger man may mean more stress for women because they are "violating social norms and thus suffer from social sanctions," which could result in a more stressful life, he said.
A "sugar daddy" with a wife seven to nine years his junior is seven percent less likely to die early — probably because she's more likely to nurse him in old age.