Well this is Miwa's first relationship and all its pretty understandable, Saeko herself was able to figure out what shes going through and indeed to someone like her thats more used to relationships and from what it seems like just casual stuff were you just have fun, someone like Miwa thats looking for all the magic of her first true love can be a pain, its all about how much each of them accept and try to acknowledge what the other one wants and needs like in any relationship.
Its hard ground to thread with someone like Miwa, a lot of trouble for everything especially since shes so shy and introverted, its all about really wanting to continue the relationship even if its a pain, still Saeko did kind of fuck up here.
People giving Rika a loot of shit when Saeko is kinda the same lol, still damn that story about her virginity was quite sad, all just to be normal eh ....
It looks like they have different values on a big scale though i dont know if at the end theyre just gonna realize they dont really fit each other or cant deal with the others bullshit and go their separate ways after both growing, Miwa is learning what an actual relationship is and how to open up to people and Saeko is to try and start a real relationship again not scared of showing her true self, and to trust others more.
Tbh i really do want them to end up together but we'll see i guess.