Well anger is a normal acceptable emotional response, it's what we do with it that can get abnormal.

I used to have an explosive temper, probably still do, I've just learned to manage and express it better.

No more yelling, cussing and throwing things, ok I still cuss when it's really bad, but I haven't broken anything in like 3 years.

Another thing that comes to mind for me is this, does your bf's anger upset you because of his subsequent behaviour, or does it upset you that he's angry and you feel responsible and cant fix it?

I hate it when my bf is angry, I immediately internalize it, and feel responsible, but I'm figuring out that his feelings are his own and he's entitled to them, its not always about me, so sometimes I should just let him simmer in peace until he can process.

I have extremely poor emotional boundaries, I absorb others feelings whether I want to or not, so it gets quite uncomfortable inside my skin at times. I swear it sometimes feels like I'm the personification of a semi-permeable membrane, but strictly for emotions.

I'm learning to separate what's mine from someone else's though, so that I don't take on too much, as its been quite an exhausting ride thus far.