Can you criticize a work for its premise, I don't think so. But it does completely dump it in the very first volume so yeah. It's about people making all the bad choices. I think this manga tries to portray them a bit more positively, like it wants them in a position where you might forgive them. The hair at her boyfriend's sounds like an out, except that it doesn't prove anything and she's the one to act out as far as both she and the audience are truely aware of, I'm annoyed at these stories that think you can justify a character's position without evidence and that it isn't all in their heads. I'm sure this manga will try to justify it but it'd be hilarious if it really was just some guy's(neighbor, or group of friends with a girl). The guy's so desperate for the girl that he's uncaring about her situation(which makes him a douche). The girl's just weak(guy is too, she's a douche as well). If she can't deal with it, she should have done something about it. Still... it's plausible, people are shitty/weak afterall. I've read the other works by these mangaka(both) and she/they/he is very thoughtful about situations, but I'm not seeing it here. Though if I'm being picky the premise was that he wanted her but she wouldn't cheat on her boyfriend, I think that story would have been interesting. The story of someone actually having to move on despite the crush because the relationship isn't possible, or about someone in pathetic desperation, while her long distance boyfriend gets to do her while he acts more like her boyfriend, or a story about realizing you can like a woman and want her in your life in a way that isn't sexual. All those would have been interesting, and possible based on the premise but the story is a simpler one where the guy and girl definitely cheat, almost right away, so I won't even consider it a spoiler. because if the premise is that she didn't want to cheat, and sexualize their relationship, it totally fails, and they do lots of sexual acts.
Frankly I am disappointed it didn't even live up to the premise. The way the girl constitutes what is cheating just makes is just very dumb(but she admits it later). The emotions aren't heavy because it's never built up despite being so slow and having apparently ten volumes to tell this story(that doesn't seem to have much meat to it, I think they could have told a better story in one). And this is the weakest work I've read by these persons; the good ones, especially the artist's, *where in they truely look at something, both sides, the faults, without forgiveness or outs.
I can't overstate how thoughtless this seems compared to their other works. How lacking it is in that feeling of emotion and heavyness. How easy it is on the characters, It's not the kind of story they make because it's too simplistic, and idealized about something that's about people doing something awful.
After volume 4: *It finally starts doing that in volume four, which goes with my criticism of how slow this is for one of their works, and it doesn't change the criticism for that time. The story's also finally getting interesting. Ironically seems people who give it low scores are doing so for the manga correcting these problems(they like it less as it gets good), guess they want the crappy version.
So this work's real problem is that it doesn't show it's cards soon enough, it just takes too long with it's first three volumes and stretches what should have been one or one and half.