Some of the symptoms you describe kinda remind me of Tourettes, even. With a stutter I believe most times there's not much to do than accept and practice so it gets reduced, and on your position, I believe you're doing the right thing with accepting it as well and letting your girlfriend speak, but I think you should still look for more medical help, or speech therapy, as these could be symptoms of something dangerous. Not many people would have done what you did for your girlfriend, I think very few people would have reacted the way you did, and thank you for that. You even went to the extent of coming here and reading more about this stuff and educating yourself, which ia insanely nice. Good luck on your path, and keep doing what you've been doing because I believe it's the right thing and just shows how much you love eachother, and these hardships will only strengthen your relationship.