I know confrontation can be scary, but you do not deserve to live like this. You are paying rent just like he is. You have the RIGHT to peace, quiet and sleep. It is his responsibility to keep his music at a level that is not disturbing others. Headphones aren't that expensive.
If you haven't given him a note, do so. If that doesn't work, make a complaint to the council. Finally, call the cops. And keep writing it all down, complete with dates, times and responses. If you see him in person, you might want to take something to record it as well.
If he gets pissed off, that's his problem. Your boyfriend is there right? There is safety in numbers. You don't have to be confrontational so you immediately **** him off (even though that may be how he reacts), but you also don't have to accept that behaviour.
The sooner you get this problem resolved, the sooner you can get back to working on more important problems, like sleep, which directly affect every other aspect of your life.
Best of luck to you.