This is hella messed up, even the ending. To be honest, the only one I like is the uke, even though he's sus. The seme is a sadist, but I also think he has a mental disorder. From chapters 4-6, I hate it. Why the hell did the seme move to Tokyo, then he had a girlfriend, duh.
The ending is also fucked up, the girlfriend Mio and seme lived together for 1 year, then suddenly Mio invited the uke, so he met them up, thus something happened. The uke kissed the seme, confessed, then seme still had those sadist feelings with the uke. Since the uke asked Mio if he hit her and she said no, it means seme didn't love her. How I wish the seme didn't get into a relationship or just broke up with Mio because it feels like him and the uke are having an affair. It's an open ending. They are both toxic.
Ore no Kimochi ga Wakaru ka