Definitely the darkest/most fucked up of Kodama Naoko's works, despite not having any cheating in it. Overall I think this was a very interesting idea that needed to be about twice as long to really be effective; with how complicated all three major characters are, and how much plot there is, one volume just isn't enough to adequately delve into the complexities and as a result it feels kind of surface level. In particular, there's lots of interesting stuff going on with Reo, from her suppressed jealousy of Meiko when they were in high school to her addiction to the dramatic lifestyle Meiko gives her in college, but Kodama doesn't really draw these threads together into a single coherent personality and as a result she feels more like a pinball protagonist that does whatever Kodama needs her to to move the plot forward.
That said, Meiko is a good enough character to basically make the manga worth reading by herself; she's almost too good for the manga, frankly. I think what a lot of people miss is that her behavior isn't solely due to her trauma from being assaulted and raped (although that is a large part of it). There's implications she's always been socially awkward and doesn't really know how to get along with people, and that plus her beauty means Reo was her first real friend, as other girls were jealous of her and the guys only pretended to be nice so they could get into her pants. The lesson she took from her rape was in this sense just reinforcing something she already believed: that she was a worthless good-for-nothing whose only value was in her looks. From all that, it makes sense why she would do whatever she could to tie down Reo, the only one she'd ever met who saw value in her as a person.
It hasn't escaped my notice either that so many people in this thread pulled out every misogynistic trope in the book to insult her, up to and including straight-up victim blaming with one person saying the rape must not have been so bad because she decided to use it to tie Reo to her, even though the manga hammers home over and over again via its flashbacks to high school that the rape was so traumatic it permanently warped Meiko's personality and her relationship with Reo. Meiko is both a victim and a victimizer, a terrible person who is terrible not because she was "born bad" but because her life experiences taught her to become that way, and while both she and Reo have made progress by the end neither of them is ever going to truly get over it. Which I find to be a lot more realistic and compelling than the "everyone goes to therapy which magically makes them healthy" ending that some people here were hoping for.
That said, I do think it's fair to criticize the pacing for being choppy and the structure of events to be more like a dumb soap opera than a realistic character drama, which is disappointing when Kodama is trying to tackle such heavy subjects. As a result, while I think this premise had potential to be her best work, it ends up clearly inferior to Segull Villa Days and Fake a Marriage With my Junior. But it is interesting enough to be worth reading if you can handle dark subject matter and mutually toxic relationships.