I suppose learning to anticipate it better would be a good approach. Because I don't see this behavior changing in myself without an intentional effort. It's pretty embedded into me. I have a few almost schizoid personality quirks that I'm trying to work out. It's kinda just burning down to a matter of effort and training to unlearn habits that I have used for so long.
It's a defensive mechanism you have developed over the years. Why try and defeat it. It's there for a reason. Someday it could save your life. Everyone has quirks. I personally have something similar. I don't like people to touch my face. Not even girlfriends. It angers me, makes me very uncomfortable. It's better to have defenses than to go through life without.
The trait doesn't bother me much, and it has proven useful multiple times. I just need to learn to relax my guard a bit when I'm around her. I don't want her feeling like I'm either unstable, damaged, etc. And I don't want her feeling like she inadvertently threatens me when trying to show some affection.
I'm not sure if there is a time when the reflex stops on its own.
I dated a guy who had the same reflex for what I can only assume were similar reasons. He didn't talk much about it.
He was 30 years old and had not been near his abuser for decades.
Very awkward. We were not together for long.
It's good that you let your girl know that it's not bc of her.
One thing that might help is asking her not to touch your face or head. Defensive postures around the body look less threatening than face blocking. She's less likely to get instinctively defensive herself if you're blocking lower on your body.
So if she doesn't reach over for your face at all, then you're not startled into raising your hands in a way that might look threatening to her.
Also, it's a reasonable compromise for both of you, so you're not asking her to keep her hands off too much of you. :)
I'd be wary of reading too much into this, it could just be one of those reflexes that are part of who you are and might have more to do w the way your reflexes are wired than anything psychological.
I have a similar thing w my back, if anyone touches me suddenly I will immediately try and get that person away from me either using elbows or turning round real quick and shoving them. Which can be awkward if it's just my trainer trying to correct my posture :/
ive never had any traumatic incident from someone trying to touch my back, it's just a reflex that's been there since I was a kid and it's just one of those things anyone wanting to live w me would have to put up with.