I think its more like he loves both Akihiko and music but he can actually only commit properly with one thing. He wants to spend more time with music and that leads him to neglecting Akihiko. Both end up suffering, Ugetsu also realises that its just not gonna work between those two and he tries to let go of him even if he has to act like the worst possible person but Akihiko just cannot let go so easily . I do think Ugetsu is a little more mature here but idk I'm really bad at explaining.