Killed by Artemis:
Homer 'Odyssey' xi. 324-5.
οὐδ᾽ ἀπόνητο: πάρος δέ μιν Ἄρτεμις ἔκτα
Δίῃ ἐν ἀμφιρύτῃ Διονύσου μαρτυρίῃσιν.
But he was not left without grief - instead Artemis killed her [Ariadne]
on Dia encircled by the sea, because of Dionysus' words.
Forced to abandon her:
Diodorus Siculus 'Library' iv. 61,
Διόνυσον ἐπιφανέντα, καὶ διὰ τὸ κάλλος τῆς Ἀριάδνης ἀφελόμενον τοῦ Θησέως τὴν παρθένον
Dionysos appeared and because of Ariadne's beauty, he stole the maiden from Theseus.
v. 51
καὶ κατὰ τὸν ὕπνον ἰδὼν τὸν Διόνυσον ἀπειλοῦντα αὐτῷ, εἰ μὴ ἀπολείψει τὴν Ἀριάδνην αὐτῷ, φοβηθεὶς κατέλιπε καὶ ἐξέπλευσε.
And [Theseus] in his sleep saw Dionysus threating him, if he did not abandon Ariadne to the god. Afraid, he left her behind and sailed away.
Pausanias 'Description of Greece'
ix. 40. § 4,
ἀφαιρεθέντα δὲ αὐτῆς τὸν Θησέα
Theseus was snatched from her.
x. 29. § 2
τὴν δὲ Ἀριάδνην ... ἀφείλετο Θησέα ἐπιπλεύσας Διόνυσος
Dionysos, sailing to attack Theseus, took Ariadne away.
Plutach 'Theseus' 20.4
τὸν γὰρ Θησέα φησὶν ὑπὸ χειμῶνος εἰς Κύπρον ἐξενεχθέντα καὶ τὴν Ἀριάδνην ἔγκυον ἔχοντα, φαύλως δὲ διακειμένην ὑπὸ τοῦ σάλου καὶ δυσφοροῦσαν, ἐκβιβάσαι μόνην, αὐτὸν δὲ τῷ πλοίῳ βοηθοῦντα πάλιν εἰς τὸ πέλαγος ἀπὸ τῆς γῆς φέρεσθαι.
For he says that Theseus, who had been forced out of his way by a storm to Cyprus, and since Ariadne was pregnant, unhappy because of the waves' motion and impatient, let her onto the shore alone. But he, running to help the ship up onto the shore, was borne away from the land onto the sea again.
Forgot:
Catullus 64.123
liquerit immemori discedens pectore coniunx
Her spouse left her, departing with a forgetful mind.
Willing to leave her:
Plutarch 'Theseus' 20.1:
οἱ μὲν γὰρ ἀπάγξασθαί φασιν αὐτὴν ἀπολειφθεῖσαν ὑπὸ τοῦ Θησέως, οἱ δὲ εἰς Νάξον ὑπὸ ναυτῶν κομισθεῖσαν Οἰνάρῳ τῷ ἱερεῖ τοῦ Διονύσου συνοικεῖν, ἀπολειφθῆναι δὲ τοῦ Θησέως ἐρῶντος ἑτέρας
For some say that she hung herself, having been abandoned by Theseus. Others say that she was brought to Naxos by sailors and co-habited with Oinaros, the priest of Dionysus, and that she was abandoned by Theseus who loved another woman.
Ovid 'Metamorphoses' viii. 175-6
vela dedit comitemque suam crudelis in illo
litore destituit.
He set sail and cruelly abandoned his companion
on that shore.
Ovid's 'Heroides' 10 (Ariadne Theseo) 5-6
In quo me somnusque meus male prodidit et tu,
Per facinus somnis insidiate meis.
[The island] on which my sleep and you betrayed me evilly,
By a crime of treachery as I slept
Hyginus 'Fabulae' 43.
Theseus in insula Dia tempestate retentus cogitans, si Ariadnen in patriam portasset, sibi opprobrium futurum, itaque in insula Dia dormientem reliquit
Theseus, whilst he was detained on the island of Dia by a storm, thought that if he brought Ariadne to his homeland, people would shame him, and so he left her sleeping on the island of Dia.
Catullus 64.200
sed quali solam Theseus me mente reliquit
But Theseus has the kind of character to leave me deserted