If you really like her, don't break up with her, just talk to her about how you feel, but be nice. Communication is key to a healthy relationship. BUT if you really just don't want to be with her anymore, still tell her how you feel and break it to her gently and tell her that one of the main reasons why you want to break up is because she doesn't give you enough space and that your just not feeling it anymore, she might try to say that she didn't know that you felt that way and that she will try to give you more space but if your really not feeling it anymore then stand strong and make sure you break it off and that you both are clear about this break up. It's better to be straight about it than string her along when your mind is already made up. Good Luck!