There is a lot to this. The polarization in male views of females is extreme, and often reflect the images of women in the media. Women are either virginal charity workers (newsreaders, BBC weather girls, childrens presenters, S Club 7) or sex kittens of some description (madonna, skimpily dressed models, weather girls from channels other than the BBC, it's late when I am writing this, use your imagination :-)

Anyway, it is likely to do with the "sex is bad" attitude that has been prevalent in christian societies for a long time, and in some Judao-Islamic cultures as well. There is a need to reconcile the physical reality of normalised sexual relations with the roles given to women by these cultures. Women are either dutiful mothers who "endure" sex for the reason of procreation, or they "enjoy" sex and are thus given over to their baser passions and to be despised. Note that in many cultures sweet, and refined women were expected to be chaste, and valued highly if this was the case. Only recently has this been removed, and the chaste thing is relegated to religion followers.

But, as we all know, attitudes take a lot of time to bedrock, and even longer to shift, especially when they are this deep. Women are still seen as lynch pins of the family, whether or not they wish to be, and as such the mother role is seen as incompatible with a free sex life. The compromise of intra-marital sex is probably what created the stable family home in the first place, with sex satisfied by both parties, and discretely hidden from the children, with constant guidance and supervision of all in the family to see that their ordinary needs were met as well. In short I do believe that women will have to suffer this particular paradox of male thinking for a while, at least until they learn to project themeselves in the media in the more rounded manner. The presence of comedy programs such as Frasier, and Mad About You did a lot to help this cause and I think we are on the right path.