She's single but she's too much into Avar to do anything, she's just dumb thinking some sexual stuff is innocent. The only way in my opinion for any action with Morganne and other man, at least with how the story advanced, is Avar willingly sharing her with other men for the sake of his company. Maybe making her film it to sell, or something like it.
As for Morganne willingly having sex with other guys without Avar knowing, considering how
archipote wrote Morganne, was a deep in love with Avar girl, that's too dumb for her own good, it would be uncaracteristic for her to lay a finger on any man other than Avar, unless he wants it, she'll feel in debt with him for what she did (and this is why she'll accept Avar with Elaine).
So if
archipote think Avar sharing Morganne to reach his company objectives (maybe even being into doing it outside work, as a punishment reminder for her that he owns her) is out of character for him, there's no way to continue any form of NTR in the story, unless dev wants to completely destroy every character building and story he wrote so far.
Just remember how broken Morganne was seeing Elaine and Avar, and how she fully obeyed them to make Avar happy anyway (while trembling from crying).