It sounds like you have some issues, that may or may not be related to your boyfriend. I’m pretty sure you already know whether or not your boyfriend is contributing to your anger.
Does he do things that make you angry? If not, then you may have to do some work on yourself.
Sometimes people end up feeling periodically angry if they have bipolar disorder. I had the misfortune of being in 2 separate relationships with (and worked with two other people) who suffered from bipolar disorder (also sometimes called manic depression). All 4 of these people were intelligent, interesting people, but they could go from being happy and funny, to angry and mean, in the flash of an instant.
Do you feel like you snap back and forth?
Also, people who have been in bad relationships before, can sometimes act as though they are “certain” that their new love interest is going to eventually treat them badly, so they preempt that potential situation by getting angry at the new person, even if the new person hasn’t done anything to deserve the anger.
Does this sound like what you might be doing?
Still other people simply have very short fuses (maybe some immaturity or insecurity thrown into the mix) and have problems controlling their temper.
Does this sound like how you feel?
Any of these problems can, and should be, examined, otherwise nothing will change, or it will just get worse.
If your boyfriend truly is a good guy, then he doesn’t deserve this treatment.
I would suggest making an appointment with a therapist to see what’s going on with you. Sometimes, a few sessions with a good therapist (sometimes you have to try out a few before you get a good match for yourself) can be immensely helpful.
If you have more of a medical problem, such as bipolar disorder, a therapist can get you hooked up with the right kind of doctor to find a combination of psychological therapy, and/or meds, to help you to be on a more even keel.
If the problem really is related to your boyfriend (or both of you) simply not being compatible enough, you should either seek couples counseling, or go your separate ways.
I wish you the best of luck.