I'm assuming you're young. Why are you in a committed relationship?
There is an old saying, find the girl who acts the way you want (instead of trying to make her fit a mold.)
That being said, is this post coming from a place of insecurity? Because being insecure leads you to make mistakes. You probably feel like you are in a catch 22. If you do nothing, you don't get what you want. If you try to change her...you will show you are insecure and push her away. I don't envy you. Personally I would charge it the game, but I've dated enough to know that I will meet more women. I don't get easily attached (or committed).
If it were me in your shoes I would probably pull back and give her something to worry about. I would spend more time with my friends and working on my personal interests/studies/job/hobbies etc. Instead of me sitting at home and worrying about what she's doing, I would give her the gift of worrying about what I'm doing. Of course depending on the real situation, it could backfire, but you really don't have a lot of options.
You could also go for the direct confrontation...tell her you dont like GNO (girls night out) and you think its too much but I doubt it will help any. Anyway, take this advice with a grain of salt, you know your girl better than we do.