I don't like the couple uestugu aki. They have too many communication issues. I understand that their love story is only based on the admiration that Aki has for the talent of uestugu. Aki just fall in love with the music played by uestugu. As for uestugu we don't know why he fell in love. That is why i think eveeven if they broke up we are not done with them.
If you compare to the relationship that aki and haru have you know that aki already said that haru saved him a lot of time. Now Aki even pass the limit where he only loves the music done by uestugu because he meet mafuyu whwhich is as talented. And eeven better because he is sharing his music. Uestugu is too egoistic to be in a relationship and i don't think he wants someone that admireadmires him but an equal, which Aki is not. That is why their ralationship is toxic and why uestugu is so interested by mafuyu.
And sorry but i won't buy a " it is better to not have two couples in the band" as a valid comment to ship uestugu and aki.
Ugetsu know there was something big talent inside mafuyu, thats why he ask aki bring mafuyu to his concert to help give trigger and inspire mafuyu. About " it is better to not have two couples in the band" this make a map line story being big. If in the band their all are couples the story taste like small world and monotonous (just my opinion) since this manga already have 3 vol. And I don't see they relationship is toxic, if toxic why aki being roommate with ugetsu for long term? if aki in his limit ( like you say), why he not move and go from ugetsu house? ( an unusual relationship will make the story more interesting). if you like a monotonous love story you can focus in aki-haru relationship (everyone is free to they oponion for good developments in this manga).
I think it's attachment. little spoilers .....don't read if you don't want to know the raws..:)
Aki wants to move away from Ugetsu. He is realizing that the longer he stays, he is never going to have an enrichment in his own music. he wants to make different kinds of music (he was so drawn to Ugetsu's music, and his sensuality,that he felt that it fulfilled him), and do things he always wanted to do. I have nothing against AkixUgetsu ship, not because I like it but because I prefer Haruki not being with Aki. they broke up long back, Ugetsu wanted him to leave because he felt if he commits to Aki he will shatter his musical career but Aki decided to stick around, they both sleep with other men. Ugetsu gets other men inside the house. Aki got raged, but Ugetsu punched him. This led him to stay with HAru, and the period of time he spend with him, Aki started to have different views on things, he felt a sense of positivity around him, and most importantly about himself, self-care.
Ugetsu might turn around and they both make an effort to repair their relationship, or Aki might end up with Haru ( it feels sensei is going in that direction, but really I'm okay if Haru finds another gem of a person like him to be with). Since it's a fiction, everyone is free to ship two characters based on how they are drawn to each of them and to have a different kind of story but what message to take from the story when it ends, matters.
The story won't be limited even if there is two couples in a group. The story won't be monoteous. At least not with his author. I can agree if there is no evolution in the character. But here, haruki is evolving a lot, he even has a physical change, not because of his feelings changing (which will be cliche), but because he made up his mind. As for Aki he is also elvoving, he was rebellous and kind of a free mind and in the latest chapter he is showing a sweetest side, not in term of love but just as a human being. So yes in a way i can love monoteous story where the world is small, with a little bit of swetness and adorable storyline like in a lot of yaoi. But in this story i won't mind a small world as itwould be well written.
Spiiler chapter 26
I am so worried that actualky aki will finish with uegutsu. Their "break up" was so fast, we do not really know what uegutsu is feeling for aki. From an author point of view, and a goid one like kizu Natsuki there is a lot to develop. So I am worried she ficused on aki and haruki and did this break up to better go back to uegutsu and aki later on.
Don't get me wrong i do think this relationship is toxic for both of them. No one even haruki was happy and if they go back together no one will be. And i do hope aki and haruki will end up together at the end. But the way it is going and as the break up was so fast i think she focused and aki haruki to go back to uegutsu aki, which i would hate....