Dear maddie22:
I am glad you don’t have contact with your abusive parents and that your boyfriend is not abusive toward you.
You carry anger and distrust from your childhood and from earlier in the relationship with your boyfriend. The injuries from childhood, those do not disappear just because we are no longer children. Time doesn’t cure those either. Maybe you can attend psychotherapy with a competent, caring therapist to help you heal from your childhood abuse. That will take care of your under the surface, easily triggered anger.
It is a good thing you talk a lot with your boyfriend. When you feel anger, share it with him without blaming him for your anger. Talk to him in a way that doesn’t attack him, accuse him or abuse him. Show him empathy and take in his empathy for you. Be best friends first.
anita