After our group reading of “Antigone” the other day, I got to wondering what happen Ismene after Antigone and Haemon’s death. I found a tidy little summary under an article about Tydeus (Diomedes father) at Greek Mythology Link, a web site created by Carlos Parada, (http://www.maicar.com/GML/Tydeus2.html) Looks like Parada based his work on Thebaid 8 and a Cornithian vase.
“(Tydeus) killed many warriors at Thebes—among which Aon, Atys, bethrothed from childhood to Oedipus' daughter Ismene…(and ten others.) Tydeus also killed Ismene, daughter of Oedipus, at Athena's instigation, while she was having intercourse with Theoclymenus”
According to the image of a vase in the Maicar collection associated with the story, Theoclymenus ran away naked. So at least in one version she ended up with a fiancee and a lover.