Beast you want that crap to stop, just tell her when she asks about the Italian place or whatever. Just say sure go for it I will stay at home and have a protein shake since I can't have anything there. If I am not awake when you get back please let me sleep.
Basically that way you are not telling her no she can't do something just that you are not going to have any part of it. Starting it off that way gives you the power. You are basically being giving in to her in a way that implies her selfishness. It also tells her that if she chooses to go without you that you are basically done with her for the night by already stating you will probably go to bed if she leaves and do not want to be disturbed.
Then if/when she asks "Why won't you come with me?" you tell her that you can't keep tempting yourself, and she knows what you can eat. If she wants you to go with her then she needs to pick a place that has food you can eat too, and if not it is okay because you can stay home and have a protein shake. Stick to the staying home and having a shake though, don't give in.
After a few times of this she is going to get very annoyed and flustered with the entire situation. She is probably gonna tell you that your diet is stupid or you don't need to be on a diet... then she may get mad and say you never want to do anything with me anymore. This is when you bust out the big guns and tell her, I do want to be around you as a matter of fact all of the time but you are not supportive to my goals and try to sabotage my efforts to achieve them. You continue to bring things into the house that tempt me and continuously ask me to go out to places that do not cater to my nutritional needs. I would love to do more things with you again but we need to meet in the middle here and start picking activities or places that cater to both of our needs.
That being said I can find something on pretty much any menu that will fit into my macros if I bastardize the menu enough. I have absolutely no problem asking for substitutions or special considerations. I add extra meat, remove sauces, pasta, cheese anything that comes with something that I can't eat I have replaced or removed. I just tell the server ahead of time that I am a pain in the ass and i know it but I tip well so bare with me. They always take care of me.