So at this point in the story am I the only one who believes Nanase cheated first. She treats Yuki way better than her other friends and let's her do everything in public that her girlfriend wants to. It can't be passed off as avoiding doing it with her girlfriend in my opinion either because in volume one she pushes one of other friends away clearly establishing a personal space bubble. I'm not saying Yuni is blameless, but Nanase even left Yuni repeatedly for Yuki even after Yuki new about them and constantly flaunted there relationship in front of Yuni. Further more Yuni wasn't looking to be doted on she just wanted some level of validation. I can't get a sense of how Yuni feels about Nanase, but to me it's obvious Nanase loves Yuki and doesn't want to risk that relationship so she strings along Yuni and manipulates her so she can have the physical contact she needs and allows her to be in control of her emotions. She never really pays attention to Yuni or values her feelings.