I was re-reading the side stories from the beginning, and Iori is a real jerk to Minami, no matter how you look at it. She beats her up and manipulates her emotionally.
At this point, I'm sure the author is doing it on purpose. She's not condoning, or promoting it, as some people would like you to think, she's just sampling various possible types of relationship between people.
Iori and Mianmi's a dysfunctional relationship, based on co-dependency. Iori comes across as a self-centered jerk, addicted on booze and mobile games, who would end up in a ditch somewhere if Minami wasn't there to pick her up.
Minami comes across as insecure, desperate to be loved, who takes being beaten up as a form of love, and with a savior complex.
Their couple lasts only because they're co-dependent in a fucked up way.
I think the author is perfectly aware that her characters are flawed and, in some aspects, dis-likable or infuriating, but that's what she wants to write (hence, the title): relationships that hold up against all odds.