If we're talking about evolutionary theory, I'd guess that a man could cheat on a wife but still stick around to help raise his child. But if a woman cheats (and it leads to pregnancy) then the man may refuse to raise another man's child, and he decides to leave. (Lions are a little harsher, and a new dominant male will actually kill cubs from the previous den leader!)

In Helen Fisher, PhD's book, "The Anatomy of Love," she actually says that the median length of monogamous pair bonds is much more like 4 years, though the reasoning behind it is similar. Once kids hit around 3-4 years old, they can walk and listen to their mother, and the need for the mother/father pair has been reduced.

Here's a relatively short article discussing it - http://www.match.com/cp.aspx?cpp=/cppp/magazine/article0.htm...

As always, this is a very interesting post. It has raised a few questions for me.

Why do humans seek relatedness and purpose?

In evolutionary terms, there are explanations of how humans with a natural tendency to seek community relationships and cooperate with others would have a survival advantage over others that did not worry about relating to others and mutually benefit each other. Further along that vein, if you would find a way that you could uniquely benefit your group by having a specific purpose, perhaps as a specific kind of hunter, learning how to defend against threats, being particularly adept at memorizing terrain and resource locations and so on, then having a purpose would make you valuable to your community for survival.

Pairing this desire with curiosity and our musings of religion results in this idea that we're here because a higher being wants us to be here and gets some value out of our existence. At the very least, we exist so that we can help others learn about religious ideas that we've discovered so that they can appreciate the ideas and benefit from what we've learned.

So what does this mean for our future? Will we find satisfying purpose in our lives from something other than religion? Can we appreciate our role in evolution, species survival and intellectual evolution?