Fun fact: Zeus was often "coupled" with the local goddess of a given region of Greece. It was a sort of mythological was to have a sense of spiritual unity between Greek peoples. You felt a lot more Greek knowing that your patron goddess had been fricked by Zeus, bringing his blessing and fertility to your land.

This would probably explain why Zeus seems to have sex with everything. Plus, he's the bringer of rain, so any earth-based nature goddess has already had sex with him in a metaphysical sense.