Advice on sexual black outs?

I (19F) was assaulted multiple times in my life before I met my now boyfriend (21M). We’ve been together three years and I was assaulted a few months before we met. I told him about it from the beginning and he has been nothing but supportive. Recently over the last year during any sexual act not everytime but most times I begin to almost dissociate. The thing is sometimes I just freeze other times I don’t even realize it’s happening till it’s too late. My body often goes on autopilot and I completely check out. I usually don’t realize it at first until it suddenly hits me and I become aware I am at this point just dissociating. It feels as if I am almost on drugs it’s hard to move sometimes it becomes hard to hear and see clearly and I get extremely itchy my skin becomes hot and I feel like I’m on fire. Once I realize what’s going on I find it hard to recall the few moments before. I however do not and have never gotten flashbacks. I am not thinking of anything before or when this happens. Thankfully my boyfriend can tell when it’s happening just by the look on my face pretty quickly after it starts. Within the last few weeks an Incident occurred that shocked both me and him. Everything was normal and during sex suddenly my ears started ringing and my skin started to crawl. I couldn’t breathe and started hyperventilating. I do not remember most of this but from what he told me I began scratching myself attempting to bang on the side of my head and unable to speak or form words. This lasted for about 10 minutes and when I finally checked back in all I remember is suddenly laying down in his bed watching a movie. Yes I am in therapy and I am getting help for it but I am so done with this controlling me does anyone know anything from personal experience or something you know that could help? It’s destroying my sex life and I am becoming terrified to have sex.