In some versions of Greek mythology, Zeus ate his wife Metis because it was known that their second child would be more powerful than him. After Metis's demise, their first child Athena was born when Hephaestus cleaved Zeus's head open and the goddess of war emerged, fully grown and armed.
THE BIRTH OF ATHENA
Zeus swallowed his consort METIS [mee'tis] (“wisdom”), after he had made her pregnant, because he feared that she would bear a son who would overthrow him.
Athena began growing inside Zeus's head. When Haphaestus cut open Zeus's head, and Athena was born, she was not born an infant. Instead, Athena was born a fully grown warrior, dressed in armor and ready for war. This is how Athena became the goddess of war and wisdom.
He Swallowed His Wife
Unfortunately, she made the mistake of telling her husband one of her prophecies: She and Zeus would have a son who would become more powerful than his father. Zeus wasn't down for a demotion, so his solution was to swallow the evidence of the prediction — literally.
He was very afraid that one of his children would kill him just as he had murdered his own father. He was so worried he started to eat his own children after they were born, much to his wife Rhea's horror!
Perhaps partly because of the strange circumstances of her birth, Athena is often cited as Zeus's favourite child. He also greatly admired her strength of character and fighting spirit. Some believe Athena was Zeus's first born child, which might, somewhat unfairly, suggest why he chose her as his favourite.
Zeus fell in love with Io and seduced her. To try to keep Hera from noticing he covered the world with a thick blanket of clouds. This backfired, arousing Hera's suspicions. She came down from Mount Olympus and begain dispersing the clouds.
Zeus finally became enamored of the goddess who was to become his permanent wife — Hera. After courting her unsuccessfully he changed himself into a disheveled cuckoo. When Hera took pity on the bird and held it to her breast, Zeus resumed his true form and ravished her.
Seven wives of Zeus
According to Hesiod, Zeus had seven wives. His first wife was the Oceanid Metis, whom he swallowed on the advice of Gaia and Uranus, so that no son of his by Metis would overthrow him, as had been foretold. Later, their daughter Athena would be born from the forehead of Zeus.
Impregnation by Zeus
Nonnus classifies Zeus's affair with Semele as one in a set of twelve, the other eleven women on whom he begot children being Io, Europa, Plouto, Danaë, Aigina, Antiope, Leda, Dia, Alcmene, Laodameia, the mother of Sarpedon, and Olympias.
Turns out Cronus had overthrown his dad, and he feared his son was a chip off the old block. One of those who sheltered the infant Zeus was a mountain nymph called Melissa. She cared for the baby and fed him milk and honey.
She may not have been described as a virgin originally, but virginity was attributed to her very early and was the basis for the interpretation of her epithets Pallas and Parthenos. As a war goddess Athena could not be dominated by other goddesses, such as Aphrodite, and as a palace goddess she could not be violated.
In her aspect as a warrior maiden, Athena was known as Parthenos (Παρθένος "virgin"), because, like her fellow goddesses Artemis and Hestia, she was believed to remain perpetually a virgin. Athena's most famous temple, the Parthenon on the Athenian Acropolis, takes its name from this title.
In his private life Zeus was quite the lothario, fathering an unbelievable number of around 100 children with many different women (but don't hate him too much – it's just a myth, after all). Of this 100, he fathered a mix of sons and daughters, many of whom were gods and goddesses, and some became great leaders.
Athena swore on the day of her birth that she would never marry or have children. The people of Athens, however, believed a story that made their patron goddess an ancestor of their founding kings.
Athena bested Poseidon by producing an olive tree on the Acropolis. Poseidon also raped Medusa—a mortal who had the reputation of being beautiful—in Athena's temple, desecrating it. Athena could not do anything to her uncle, so she took vengeance on Medusa by turning her into a woman with snakes on her head.
Hera. The most famous of Zeus' wives, Hera was also the sister of the father of the gods, and the goddess of women, marriage, family, and childbirth.
Aphrodite later and of her own volition had an affair with Zeus, but his jealous wife Hera laid her hands upon the belly of the goddess and cursed their offspring with malformity. Their child was the ugly god Priapos.
Ganymede (or Ganymedes) was a young man from Troy. His beauty was unparalleled and for that reason, Zeus abducted and brought him to Olympus to serve as his cupbearer and lover. Ganymede's myth is an important step in the history of homosexuality.
Suffice it to say that Zeus was constantly involved in extramarital affairs. Throughout the various and sometimes contradictory myths composed by Greek authors, there are at least 20 divine figures with whom he consorted, and about twice as many mortals.
Under the name of Callithyia, Io was regarded as the first priestess of Hera, the wife of Zeus. Zeus fell in love with her and, to protect her from the wrath of Hera, changed her into a white heifer. Hera persuaded Zeus to give her the heifer and sent Argus Panoptes (“the All-Seeing”) to watch her.
They fight constantly over each other's decisions, and Hera resents Zeus due to his affairs and womanizing behavior. Sometime during her marriage, Hera would start an on and off affair with Hades that would end around the "80s." It is unknown if Zeus was ever aware of the affair.
Zeus slept with his own daughter, Persephone, because she was there.
Zeus and Hera play important roles in Greek mythology. Zeus is the Greek god of the skies, and Hera is the Greek goddess of marriage and birth. Hera is also known as Queen of the Gods because of her matriarchal role in Greek mythology. Together, Zeus and Hera had three children: Ares, Hebe, and Hephaestus.