People who say one thing to you and another thing behind your back are not worthy of your time, and are less worthy of your affection.
I don't think I can put it more simply than that, my friend. When we allow ourselves to fall for people who are no good, we often have a hard time breaking away...it becomes a downward spiral and that "tug of war" you speak of becomes a battle you cannot win. The best idea for you now would be to break that cycle and just leave.
She wants more time? She can have all the time in the world...by herself. It is not worth hanging on and hanging out until somebody makes up their mind. All too often that decision is in the negative, and you've been holding out hope and keeping your calendar free while hoping for a miracle. It's a setup for a letdown, and you deserve better than that.
Instead, why not explore other avenues? Hang out with friends, leave this girl behind, and enjoy the good life! There is far more out there than someone who wants to keep you in her coat pocket for when things get rough. As tough as it may seem, by leaving this girl behind you can find better things ahead. And that's what it's all about. Good luck!
BruinDan, "Number Three," PHOM
Beware the naked man who offereth you his pants.