So, we got people complaining about how this is a bad way of resolving what could have been a "compelling" conflict, but I just got a new idea. This is actually great, and goes along with the laissez faire attitude of the story. The conflict of Shizuku coming in to ruin Minami's happy life isn't actually a conflict because of what's happened beforehand. Her relationship with Iori, which was spun to look purely physical, has grown to be so much more that Minami has a reason to leave Shizuku. Previously, she would've been, "Nah, you right," but now she has someone she cares deeply for and knows she doesn't have to put up with Shizuku to be accepted. This is (as far as I can tell so far) a very happy and feel-good story. This conflict is resolved simply because Minami is in a good place now and knows it. Unlike so many other tropey characters, she doesn't hide her happiness from herself and knows what she wants and how she deserves to be treated. Iori, likewise, doesn't have to do the typical beat-up thing because their relationship doesn't need the additional conflict. It reaffirms it when Minami returns, and that's all they need. I seriously love this story, and love it more the more I think about it. Easy favorite.
I also think Shizuku has the abuser complex where she's convinced Minami will come running back, but it's an afterthought just to show that she refuses to move on, which is just another victory for Minami who's grown past that line of thinking.