I'm thinking of sacrificing a 4-year relationship to music
Why would you sacrifice your relationship to music?
It contains me and I miss having my freedom.
I don't think you should ruin a relationship over music. You should try to find a compromise between your partner and creating music.
I don't know if I can handle both of them at the same time.
I understand your frustration but you should really try to find a balance between the two.