Zeus weakness were woman he was attractive to anykind mortal and inmortal he was known as a "womanizer" he got with anyone he saw instantly didnt matter is they were family at the end he married his sister hera.Yes zeus is married with his sister Hera I know this sounds weird but in those times Zeus wanted only his family to have the great power of all gods so thats why he married Hera but he also had kid with his other sister Demetre which he was not married to her .you he also cheated on her with almost every other goddess