Lol, maybe this is what Citrus wanted to achieve?
(Netorare: Cheating or being unfaithful to a significant other, lit. "taken away by sleeping with", abbreviated NTR)
I came for the yuri content, stayed after the first episode because of the erotic scenes (let's say I liked the pacing and the balance between romance and sex) and watched the whole show because of the story. Now looking back, I must say, this show really has substance. (Don't think about a mindless hentai/ecchi, please. It contains explicit sex scenes, but nothing graphic.)
I really appreciate when besides love, sex is not out of the equation, and honestly, I'm pretty bored of those innocent, platonic shows where everybody gets a heart attack just by holding hands and maybe we see a kiss at the end and nobody knows what the heck they want or what's going on and everybody is warm hearted and the bad guys are just a little bad. (Kase-san and Morning glories is a stellar example for the opposite, where they actually start with the kiss :) and pysical attraction is not ignored - especially in the manga -, but that's a more pure hearted show than this one.)
Thing is that NTR is dirty and the world is cold. But not unbelievably dirty, even so, it seems pretty realistically dirty. There are more twisted things happening in real life, so it's just about your personal preference, if you are interested or not in the love story of four more or less wrecked teenagers. We get here a good girl-bad girl, good guy-bad guy setup and it's pretty obvious where they are coming from ("I don't like girls, but I like sex"). Their morals, their motivations and intentions are clear, their actions are justified and their communication is straight, which is a great achievement in itself. It's a must anyway, because episodes just run under ten minutes each, so there is no time to waste.
So, yeah, the characters are messed. I mean, some of them are pretty messed. But unlike in Citrus, where one of the girls is clearly mentally ill and would require professional help - which makes the show a sick experience to watch for me -, NTR comes close to it, but doesn't cross that line.
It's not for everybody and not just because of the blatant sex scenes, yuri content, abusement and exploition between the characters. Also because, like in real life, there is no justice served at the end. The ending is positive, satisfying, well founded, does not seem rushed, but it's bitter and sweet. Obviously, not everybody gets what they deserve or desire. And this level of realism is why it became one of my favorite shows in the genre. (The other one is Bloom Into You, but that's just too innocent.)