I’m no therapist, but I’d suggest you try to make music sobbing something you could do together. If that’s such a big part of his life, the last thing you want is for it to be a point of contention between you.

Maybe the next time you’re both listening to a song that you both like and you’re both in a good mood just say, “hey, can I tell you something? I like to let you know what songs I like and don’t like because you listen to so much music and you might be able to suggest some music that I would like and will broaden my palette. But when you just tell me the song sucks, it just makes me feel bad about myself.”

Or something like that. Then, if he ever starts making you feel bad, you could ask if he has any suggestions that are similar, but good. Hopefully he gets psyched about sharing music with you, because that’s one of those core traits of a person’s identity that should be shared in a relationship.