I didn't read through all the other posts, but I'm sure you got some great suggestions. If I were you, I would sit down with your girlfriend and fully explain what this lifestyle is all about. I'm assuming you haven't done this. If you have, and she still continues to be frustrated with your lifestyle, then maybe you do need to think about whether or not this is the relationship for you.
Before you think about breaking it off with her though, try compromising. I hate going out to places that have gross food also. I completely agree with you! Most restaurant food is filled with crap that I probably can't even pronounce. Maybe you can compromise and agree that you will go out to a restaurant once or twice a month. Honestly, I think that once or twice a month is a good amount of times to go to a restaurant. Going out does get costly. So in addition to being healthier, choosing to stay at home and eat can also save you money!
Perhaps you can also chose one night a week to stay up with her and watch a movie or something like that. It's not good to go to bed at 2am every night. But staying up until 11pm once a week is not going to wreck your health.
I'm not sure what time the sun sets where you are, but I'd be annoyed if my bf wanted to go to bed at 7pm or something ridiculous (I'm assuming it's currently a bit later now, though?!) As for the rest, most restaurants you can find something fairly primal to eat, a steak and veggies isn't difficult!
I suppose ultimately it depends on how well you listen to each other, and how supportive you can be of each other's goals etc. If you can't respect each other, it's not going to work.
IDK man, it sounds like you've got the problem, not her. Especially if you sold yourself in the beginning as someone who likes to go out and do things and try different places. I've had that happen to me a surprisingly large number of times: Man who says he loves going out and likes different kinds of foods and doing fun things turns into someone who won't leave the house and will only eat at two restaurants.
Personally, I probably have a more restrictive diet than you, as I'm Primal and very low carb, and I still manage to eat out wherever anyone wants to go. However, I've made it a personal goal to not let my lifestyle choices make other people's lives difficult. I've had too many (mostly new vegan converts, incidentally) make my life miserable with their diets.