On a slight digression, I remember reading somewhere that amongst men and women that know each other reasonably well, the women start looking uglier to the male eyes over time, why the familar male face looks more attractive to the female over time. I am not necessarily talking partners here, just men and women that interact with each other reasonably regularly through work or sports clubs or wherever.
I have found that to be true myself - I quickly start noticing the flaws in the women I meet...they never look as good to me the second, third, fourth time we meet etc, as compared to first time I saw them.
Maybe it is an evolution thing where us men are programmed to plant our seed in a woman a few times then move on to another when she doesn't start to look so hot anymore.