This is something I don't understand. If Hera hates Zeus' infidelity, to the point of cursing his lovers and even trying to overthrow him, why not marry someone else?
Zeus is more powerful than Hera and all the other gods. In fact, he is even stronger than all of them put together, if we take his word for it (Iliad 8.19-27). This is what Zeus says to Hera after he realizes that she had tricked him into falling asleep in order to help the Achaeans:
The sire of gods and men had pity on him, and looked fiercely on Juno. "I see, Juno," said he, "you mischief-making trickster, that your cunning has stayed Hector from fighting and has caused the rout of his host. I am in half a mind to thrash you, in which case you will be the first to reap the fruits of your scurvy knavery. Do you not remember how once upon a time I had you hanged? I fastened two anvils on to your feet, and bound your hands in a chain of gold which none might break, and you hung in mid-air among the clouds. All the gods in Olympus were in a fury, but they could not reach you to set you free; when I caught any one of them I gripped him and hurled him from the heavenly threshold till he came fainting down to earth; yet even this did not relieve my mind from the incessant anxiety which I felt about noble Hercules whom you and Boreas had spitefully conveyed beyond the seas to Cos, after suborning the tempests; but I rescued him, and notwithstanding all his mighty labours I brought him back again to Argos. I would remind you of this that you may learn to leave off being so deceitful, and discover how much you are likely to gain by the embraces out of which you have come here to trick me." (Iliad 15.14-33; there are similar speeches in book 8)
The myths have Hera trying to thwart Zeus many times, and she always suffers for it. She couldn't simply decide to get divorced from the king of the gods, if he didn't want her to separate from him.