Cheating on one's significant other is common in Greek Myth. I have only found four gods that remain faithful: Hera, Amphitrite, Eros and Psyche (while gods that didn't marry can't exactly cheat). Examples of infidelity are:
The following is a list of deities regarding whom I have found no occurrences of stories about them being unfaithful to their spouses.
(It might be a noteworthy consideration that most of them are female deities.)
The sea-god Nereus and his wife the Oceanid Doris
The sea-goddess Eurybia, wife of the Titan Creius
The Titaness Tethys, wife of her own brother Oceanus
The Titaness Mnemosyne, Goddess of Memory, who, in Hesiod's Theogony, is Zeus's fifth wife
Erebus, the primaeval personification of darkness, who was married to the night-goddess Nyx
Hemera, the primordial personification of daytime, who was married to Aether
Uranus, the original sky-god, who was married to his own mother Gaia, the Earth
Sidenote 1: The poetess Sappho says that Eros was the son of Uranus and Aphrodite, but Theoi.com interprets this as meaning that Aphrodite herself was born pregnant, with Eros in her womb, she herself having formed out of the severed genitalia of Uranus mingling with the salt-foam of the sea. Besides, the more common parentages of Eros do not involve Uranus.
The river-god Hydaspes, in India, who was married to the nymph Astris
The Arcadian river-god Ladon, who was married to Stymphalis
The Sicilian river-god Anapus, who, in Ovid's Metamorphoses, is married to the nymph Cyane
A few Oceanids: the aforementioned sea-goddess Doris; Electra (wife of the sea-god Thaumas); Meliboea (wife of King Pelasgus of Pelasgia, which later became Arcadia); and the youngest Oceanid Eidyia (wife of King Aeetes of Colchis).
Iris, wife of Zephyrus
Hebe, who married Heracles [Hercules] after he became a god
The Nereid Thetis, wife of the Myrmidon king Peleus
The Nereid Iphianassa, wife of King Enydmion of Elis (though there are different versions of who this king's wife was).
Rhode, wife of Helios
Benthesicyme, who married a king of Aethiopia [Ethiopia]
Nephele, wife of the Boeotian king Athamas
Sidenote 2: Regarding Eros: in Book 32 of his Dionysiaca, Nonnus quotes Hera as devising an elaborate fiction by which to deceive Zeus. In it she says that Eros has become infatuated with the Oceanid Rhodope so much so that he has even abandoned his duties as the god of love.
Since Nonnus does not mention Psyche, who, besides that, appears to be a purely allegorical character invented by Apuleius, it is unclear whether Eros is at this point is to be understood as being married. The point might be moot, however, since the business with Rhodope could all be part of Hera's lie.
Sidenote 3: Algaia (or Aglaea) shouldn't be on your infidelity examples list, by the way. She was legitimately married to Hephaestus after he had divorced Aphrodite.
I think Dyonisus, in fact, was never unfaithful to his wife, Ariadne. I mean, he did sleep with others, but only before marrying her, and even meeting her for the first time.
Hades is generally believed to have been faithful to Persephone.
The story of Minthe (which you mentioned as evidence of infidelity) isn't about Hades's infidelity, it's about his crazy ex-girlfriend. It's a myth specifically about Hades REFUSING to betray Persephone, even in the face of an ex-lover who wants him back.
"Mint (Mintha), men say, was once a maid beneath the earth, a Nymphe of Kokytos (Cocytus), and she lay in the bed of Aidoneus [Hades]; but when he kidnapped the maid Persephone from the Aitnaian hill [Mount Etna in Sicily], then she complained loudly with overweening words and raved foolishly for jealousy, and Persephone in anger trampled upon her with her feet and destroyed her. For she had said that she was nobler of form and more excellent in beauty than dark-eyed Persephone and she boasted that Aidoneus would return to her and banish the other from his halls : such infatuation leapt upon her tongue. And from the earth spray the weak herb that bears her name."
Basically Hades used to be with Minthe, but when he married Persephone he broke it off. Minthe got pissed and wanted Hades to "return to her," which necessarily means he was no longer with her, and started shit-talking Persephone, so Persephone kicked her ass and turned her into a plant.
Of course, Persephone had a few lovers of her own, so Hades's loyalty wasn't reciprocated. But I guess that's what you get for forcing a girl into an arranged marriage with her uncle...
In real Greek mythology, when it comes to Persephone and Hades, that NEVER happened. Persephone and Hades were faithful to each other.
NO Ancient Greek author ever claimed otherwise. And NO Ancient Greek myth, ever claimed that they were “unfaithful” to each other either.
That’s a ROMAN FABRICATION, invented by Ovid, a ROMAN author, for ROMAN mythology, as a ROMAN myth.
And in the original Roman myths, neither Pluto (Hades) or Proserpina (Persephone) had an “affair.”
In the original myth of Minthe, Proserpina (Persephone) turned Minthe into a plant before she could have a liaison with Pluto (Hades).
While in the original myth of Adonis, Proserpina (Persephone) NEVER even appeared. She was only ever SHOEHORNED into that myth, by later Roman authors who were unfaithful to Ovid and to the original myth. Making it invalid and non-canon to the original myth.
And clearly, since that’s a ROMAN fabrication, it’s also invalid and non-canon to Ancient Greek mythology, the original mythology.
In real Greek mythology, both Persephone and Hades, were faithful and loyal to each other. At least according to the Elysian Mysteries (Persephone’s main cult), who believed that Persephone and Hades had a faithful, and apparently, a loving marriage too.
And if you’re not going to acknowledge Persephone or Hades, then you shouldn’t acknowledge Hera either. Since according to some sources, Hera slept with Dionysus. No Ancient Greek author ever claimed this, but you honestly seem to think that fan fiction is “valid.”
While Hephaestus was legitimately married to Aglaea.
