For starters read this entire thread:
That will give you a whole lot of information.
And I also applaud your support of your girlfriend!!!! My hat is off to you!
If you eat or drink gluten then your girlfriend can get glutened when you guys kiss unless you brush your teeth very thoroughly before any lip locking happens.
I do not eat out at all. Not worth the risk to me. I have the skin presentation of celiac disease called dh for short (dermatitis herpetiformis) and the antibodies get deposited under the skin & can stay there for a long, long, time and make you itch like there's no tomorrow so I just do not risk eating out. I do not immediately get gi symptoms to tell me I have been glutened.
Yes, when a celiac digests any gluten, even trace amounts, it damages the villi in the small intestine so she needs to be as clean as possible all the time forever.