This is a HUGE topic on my mind lately and I believe that PUA material has helped me to understand it.
Here's the quick and dirty:
Dudes have to be strong to compete but (imo) dont really want to have to be strong all the time. therefore they compete to find/win a female. They create a safe environment in which they can feel safe from predators (and other dudes) and enjoy the non-competitive sex they've fought for.
Chicks want a strong dude.. so (pua 101) they shit test. When they find a dude who is strong enough for them they allow themselves to be "caught". They then settle and nest and enjoy the feeling of being secure (no more game).
Now the problem: Because dudes dont want to have to be strong all the time, and have carved out a safe environement in which they dont have to be, they soften up towards their woman. the problem being that the shit-tests never really stop.
SOOO... whereas the dude thinks he's giving to the woman what she wants (by being soft) he's actually SPAM his power. This leads to suckage on an epic (yet all too common) level.
Research "betaisation" and read this article:
http://puarticles.blogspot.com/2008/01/ ... ified.html