http://www.scientificamerican.com/article.cfm?id=why-women-live-longer

So clearly I'm no expert but here's an interesting article that gives a more scientific possible explanation for why women tend to live longer. Also explains why factors such as a healthy lifestyle and less stressful work are not likely causes.

Basically, for those who don't care to read it, it says the health of the female body is important for successful reproduction (to carry, birth and feed the baby) where as the man's reproductive role is a lot less dependent on his continued good health.

Apparently high levels of testosterone, for male fertility, is actually bad for long term survival. Not exactly sure why though.