This opinion is from a stoner thats into personal responsibility...
You must live in the present and listen to your conscience. You should NOT make a decision in the present because of what someone else MIGHT do in the future. Your choice should be about how you feel NOW, NOT how you may feel if she stops. As long as your decision is based on something that she may or may not due then she IS in fact in control of how you feel.
Just think about it... If you stay in a situation that does NOT work for you just because your in love, the message that you are sending to your girlfriend is that even when she does something that does not work for you that you will just put up with it, and she would be correct. This will be the cycle that your relationship stays in because, after all, why should she change. This is no foundation upon which to build a relationship.
BUT,
if you take care of yourself by telling her that although you support anything that she chooses to do, her current behavior does not work for you, therefore you cant be together. Keep in mind, you are NOT asking her to change anything. You are just stating the facts about what does not work for you. Any changes that she may choose to make because of this information will be her choice.
One of Two things WILL happen...
She will either take you seriously and make the necessary changes while you are apart and then return to your life with something to offer and she will have a renewed respect for you. This IS a good foundation!
OR
She wont take you seriously. She wont care to make any changes and will continue to try and get you back while still doing what bothers you. In the mean time you'll be taking care of yourself and find another girl that DOES work for you and forget about the last one. Also a good option.
Maybe an easier way to sum it up is... "Dont stay somewhere that makes you unhappy even if you feel compelled to do so."
Good Luck!