Oh grasshopper, the upper hand will never be permanent (look up marriage haha). But like I was saying if she gets things more and more her way, she will eventually lose interest and you'll get less of that. Once she knows what you want most, it starts getting used as a bargaining tool. You can go and say she cares more about the relationship, but if I remember correctly she hasn't spent a dime except for a case of beer. So if you look at it from a goods perspective, at the moment she's giving up the occasional poon in exchange for free food and drinks (when it's convenient for her). But when you are getting the poon in exchange for say, nothing, then you will have the true upper hand.