Men are socialised to be like that about sex. The result is an abnormal obsession and entitlement.
I would agree with this. There's evidence to suggest that, prior to the Georgian period, cultural perceptions of lustfulness were very much about female sexuality. Men, on the other hand, were much more passive and encouraged to put up with sex for reproductive reasons.
This makes a lot of sense when you consider the cultural impact of Puritanism, and the legacy of the medieval church and its attitude to male sexuality, considering, in particular, the connection between the church and male positions of power.
In this context, women are "lusty" because they desire pregnancy, their "wombs drive them." Men, however, must separate themselves from bodily feelings in order to get closer to God.
It's only in the late 17th century that this starts to shift. And even then the full reversal doesn't peak until the Victorian period.
My gut says it's something to do with economic change, urbanisation and industrialisation.