My partner and I have been together for about 8 months, 4 of which have been spent dealing with my PTS...
Oh, I have been there. I only usually get triggered while being intimate, until lately but that's another post. I have full blown flashbacks during sex. Which usually involves crying and memories that I had never remembered until that moment that shakes me to my core. After that no one wants to have sex anymore and I am so distraught. I recently had a partner that looked up how to help people through flashbacks and they understood better than anyone else. Ask him to read upon it so he can better understand. I had a cue for my significant other during sex. If I every felt like I was going to flashbacks I would pat them a few times quickly and they knew to stop. They understood it wasn't them. Be open and honest with what you feel comfortable with. If you know your triggers share them with him. For example the people I have been with know not to touch my neck due to my trauma. It's a big trigger. You may learn new triggers and just share those with him when they arise. He definitely cares about you. Also, don't push him away. A guy loves to help a person he cares about. Let him learn how to help you. Good luck.