The end disappoints me while most of the chapters we know from Dad's perspective. He used to have a sweet child, who grew up frustrated without him knowing, and the relationship between him and his wife went stone cold, and from that point, he's more infatuated of the love he had when he and his first wife got married.
He's sexually frustrated, but we won't find any therapy or nor the stoic culture let us talk to one. Shiina has had her own problem, and this is more her ever positive ending of all of them, hope it works well. The irony of this manga is for all Dad's perspective we have all in the chapters, with the ending shows almost none of him. We only know he tries to reconcile but fails, and then nothing else. Is he going back to Shiina? Doubt that, but it seems his life hasn't gone worse too far yet.
However, the Wife "needed to" divorce from him just to get back to her pretty self because she had to support from herself instead of her husband is... I dunno, how to say it. In one way, she's always been in good term with her daughter before she went to Juvie. She's been complacent with her husband she took him for granted, and divorced him when things went awry. Basically, they both discarded him when he's not useful as a husband/father figure anymore. He's disposable at any aspect.
The husband is still wrong to make a move toward a minor, that's it. And not to mention, his sexual experience with Shiina was outright repugnant, powerless, and half-assed escapism of his own mind, especially when Shiina R-ed him, in front of his daughter, as a revenge to her. He didn't enjoy it one bit. Even in his sexual escapism, his mind is somewhere else, in chaos. Looking for something, running away from something, and never in a positive state. While in assuming power-dynamic, in the end, ironically, it's Shiina who was once in control, and for revenge. He never was. He tried in his unstable psyche, but it still ended up wrong to him.
Aside of that, all's are B-class cheap drama especially with the time skip, but it's obvious we don't see the daughter have the humiliation and the bully she's done to Shiina. We only see her being a celebrity. And the Mother gets back pretty again.
In short, the husband had a lousy-ass life when he had ungrateful bitch of a daughter and a ugly wife, making him unstable and low-morale, and when they divorced, the ex-wife become pretty again and the daughter became a celebrity out of from the juvie.
Whereas, we see husband's frustration for what, 16 chapters? We don't know if he's being stable or even happy. It feels frustrating.