Would it be a rug pull? Almost nobody wants to see them together. The only rug pull would be if Sakura never learns the truth and just gets to be happy.
What expect to happen is it was a one time sex and isnt with the guy. Shes been moping around pretending to be happy but isnt, not because she cheated on Shinobu but because she thinks he abandoned him.
What i want to happen is that she learns the truth and is crushed and tried to get back with Shinobu, but Shinobu stays faithful to Fumi and Sakura has to live with what she did, story ends with her successful and achieved her dreams but has to live with the fact that she destroyed her relationship to get there.
What I think happens is that somehow Shinobu and Sakura wind up together, he has to do the work to forgive her and she doesnt have to do shit but come back and apologize after learning the truth. I truthfully believe Airi doesnt believe cheating is any big deal so, I bet she gets them together because she "loves" Shinobu, even after fucking him over in like every way possible.