@BoyfriendqwithPTSD - welcome. I can see you have already had a lot of positive feedback already, but I figured, another point of view, especially from another male, wont cause any harm.
I suffer from PTSD, anxiety and depression and have regular panic and anxiety attacks. To me, all of this is incredibly real. It feels as though my every belief, my every core betrayed me. I know that I am not thinking rationally, I know that I am not being fair to the ones I love, I recognise that my thoughts, my fears, my self loathing are not rational, but I am unable, in those moments, to be able to prevent them.
In my moments, I will be unable to express my true emotions as my brain will be in a full state of panic, full of insecurities, riddled with self loathing and patheticness because, as a man, I shouldnt feel weakness. Most of these will come out in a negative way, either by arguing with my loved ones, or doing negative activities. Almost every single time, I will break down into tears and will isolate myself from everything and everyone as this is the only safe place I can go. I dont go into shops much because people are too much of a threat to me, I dont socialise for the same reason. Finding faults is an easy way to take the pain away from me, so I dont have to think about me, and what is happening to me, and how insecure I feel. PTSD is a very selfish infliction, and I know I am being selfish, but at that moment in time, its the only thing that I can do to keep myself semi functioning when all I want to do is drive into the nearest bridge pillar.
Its good that you are learning about it, teach yourself as much as you can. Everyone is different. I eventually learnt what my triggers were and when I could feel an attack coming on, but everyone is different. The important thing to notice is this - PTSD is very real, the effects is very real. If I may give an example, if I can ask you to close your eyes and think of a time when you were truly absolutely petrified, you feared for your life with every ounce of your body, be that when you were a child (real or not). Now imagine, when you were in that state, were you able to talk effectively, reason effectively, love effectively, function in a socially acceptable manner? Probably not, at that time, you were in full self defence mode, adrenaline was careening around your body and your brain was just screaming at you to protect yourself. You couldnt turn this off until your brain told you that the threat had gone. Whether or not this threat was actually real is irrelevant, to your brain, it was. This is how PTSD affects, certainly me, a trigger is something which reminds my brain of the traumatic incidents which then send it into defence mode. I start scanning for threats, I want to run, to fight, to hide, to protect, but I dont know what from yet. Panic sets in, the anxiety heightens, my body is in full protect mode, I cant remember what you say to me, I cant express any feelings. All my body wants to do is protect itself - thats it. Your body ultimately, will always protect itself until its last breath. It will shut down organs, slow heart rate to prevent blood loss, shut down pain to function, to evade, divert all oxygen and blood to the heart, lungs and brain, because we can actually survive without anything else when you think about it.
For me, an attack starts, my vision starts to pinpoint, my hearing heightens, I can hear so much more, listening for the threat. I lose my ability to talk, I will just go silent, I will feel the adrenaline dump into my system, my body will start to shake. If I dont catch it by this stage and either leave or try to calm myself down, my body will go into complete defence mode, everything suddenly is a threat, and to me, its a real life endangering threat, I will lash out, I will attack, I will cry, scream, cry and break down in hysteria. I wont remember much of what I do and emotionally, I become a complete wreck.
Your brain gets full of mess basically, mine feels like it assesses any new information that comes to it and if it is not an immediate threat, or validates the fears, then it feels like my brain just says - "Nope, I dont need to know this information, I am waiting for the danger, I know its there, cant waste my time with information that I feel is pointless". Unfortunately, this pointless information could be important to you, the loved one, but to his brain, its not as important as the incoming danger.
I am also quite emotionally dead, why? Because, I am tired, my brain is exhausted, each and every attack makes me just want to sleep for hours. (Think of a time when you just couldnt stop crying, and afterwards, you just fell asleep because you were exhausted.) Now imagine that all the time, constantly. Emotions become dead as its too hard to think about them, to deal with them, to process them. Its easier to hide, to ignore, to pretend it doesnt exist, because my brain is so tired, its barely keeping itself afloat, let alone functioning effectively. Unfortunately, this leads to hurting our loved ones. Not intentional at all.
Make sure you have your own support, be that a good friend, family, your own therapist, and learn your limitations. You cant be his girlfriend/wife and his therapist. Be truthful to yourself as you cannot be a rock if you are floundering yourself.
My wife doesnt know when an attack is incoming, yet my best female friend does. She detects it in my body language, little shakes, my conversation lacking or slowing mid stream. Just let him know he is safe, I dont mean by telling him (he will likely know he isnt being rational so telling him something he already rationally knows may not help), but by a touch, maybe even taking control and removing him from the situation. He will know his thoughts are irrational but they cannot be rationalised at that time, in the heat of the moment. Hold him, hug him, touch his arm, remove him from the situation until he feels safe.