Dating Younger Women - A Complex Morality

You walk into a bar, and you see an older man dating a much younger woman - Is that guy a sleaze or a legend? Is he to be admired or scorned? Is he doing something inherently wrong? Or is he just following a biological imperative? 

It's easy to assume that women are just jealous that these men aren't interested in them once they approach their 30s.

But actually, there is a fascinating level of complexity in the question of older men sleeping with and dating younger women and age gap relationships in general that most people don't consider.