Madoka is terrible, her character is easy to hate and when it comes to her arc and you get her side of the story, you'll think "oh well she had a rough time", then she leaves her clearly unhappy marriage and will finally live for herself and that was great, it was sort of a redemption arc.
When Joe comes into the story you'll start to think you understand where this is going for, Madoka left, Yuzu will leave with her baby father AND old love, and Ryuu will be with Koharu only, but Yuzu decides to stay and honestly, it was still fine, not what I was rooting for, but it's ok, I think the relationship between the 3 of them is still better than with Madoka.
The thing is, Ryuu loves Koharu, the whole manga you can notice how he feels different towards her comparing to how he feels towards Madoka and Yuzu, and that's because they both have story together, but he had so much trauma that he just got everything in his life twisted. You see some character development in him as the story folds, then he throws everything in the air when deciding to cheat on his family with MADOKA. At this point, I just wanted him to have a miserable ending.
When Koharu leaves it STINGS, Ryuu for the first time realizes something, all the flashbacks and memories he has with her hits him, like he said, "what you gave me was happiness", but the author for some reason still wanted to keep the whole "polygamy good all the time" thing.
So, Koharu now lives by herself with memories shattered by her unfaithful ex-husband. It hurts. I cried a lot. Then Koharu decides to come back.
She decides to come the f*** back. To her unhealthy relationship, and Madoka comes back to, so now you have two women on an unhappy marriage, because even if they get used to it, they will still feels the same at some point. The only one who ends up on a good spot is Ryuu, he is now comfortable with having women willing to to anything because of him.
After all, it's a good story, it doesn't have to end like I want to in order to be good. I agree that some things are left unsolved, some other things feel weird, but still, you have characters that feel real, jealous, filthy, happy, sad. I don't like the ending, but I like the manga, it made me feel something and I value that on a story.
