The argument with your boyfriend is hugely insignificant in relation to the mental health struggles you are going through. I hope you have medical support for what I am guessing involves PTSD and/or C-PTSD, and I hope you have a therapist who can help you process everything you have survived and continue to survive. He can't be your therapist or your doctor, and, you're right, he hasn't experienced it and can't truly understand it.