Because he had so many affairs with other women.
Hera is jealous in the majority of the myths she appears in because Zeus is always cheating on her. In the myth of Hercules, for example, Hera is jealous because Zeus cheated on her with Alcmene.
Hera.
Echo was a forest nymph protecting Zeus from his jealous wife, Hera. Hera cursed the nymph's voice so that she could only repeat what was spoken to her. She distracted Hera while Zeus went back to Olympus after sneaking out.
Hera was jealous of anyone who caught Zeus's eye.
Hercules. Also it wasnt Zeus, it was just Hera because she was jealous that Zeus had another child with a mortal
First off, everyone can be naturally jealous. Second of all, she was extremely jealous of people because of Zeus's innumerable affairs with woman. She wanted Zeus to spend time with her, and so Hera decided to take her anger out on Zeus's lovers and Zeus's lover's children.
She was only jealous of the ones that Zeus had had with other women because they meant that Zeus had cheated on her, because she was his wife
Hera is the Goddess of marriage so she would be jealous of her husband Zeus's affairs.
Hera was insanely jealous of the women that her husband Zeus was having affairs with.
Hera, wife of Zeus, was the goddess who had a good reason to be jealous
he constantly cheated on her which in turn made her jealous Zeus and Hera were the prototype for what it meant to be male and female in ancient Greece. Zeus was domineering, virile, and philandering, not out of disrespect, but because it was his nature. Likewise, Hera was the paragon of fidelity. She was passive-aggressive, demure, and jealous of Zeus conquests, going so far as to manipulate circumstances against them. This is how the Greeks viewed men and women.
Hera was most famous for punishing those who had affairs with Zeus.