I've read this manga years ago and I forgot the title. The plot revolves around a boy with split personality; one rebellious and the other kind. He plays the violin and constantly practices it but the rebellious side hates it so whenever he takes over, he tends to escape. While he escaped, a nice guy befriended him and during the course of the manga he reciprocated the nice guy's feelings. The kind one also loves an asshole in his school who even tried to break his fingers one time. Drama ensues and the rebellious and the original kind side had an inner self conversation. The rebellious side faded away and the only the kind personality remains. The uke patched things up with the asshole but his love for him wasn't that great anymore and eventually went overseas to continue his studies(?). After many years, the uke returned to Japan and was welcomed by the nice guy who now works for him as his assistant(?). It was an ambiguous ending but it was obvious that the uke and the nice guy ended up together.

I remember every detail of that manga because it was one of my favorites. I'm ashamed to even forget it. T_T

G-senjou No Neko