You know this site is full of 50-50 stories. Like who folded the most laundry that week. Bickering like unhappily married couples. Yes your gf probably is a little self adsorbed. But I still say you are nickle and diming your relationship. So let me explain it this way.
Suppose you break up with her and you go out looking for another prospect. You meet this nice hot waitress and you ask her out. She is a college student, and most likely living paycheck to paycheck. Are you going to expect her to pay 50-50?
If the above girl is worth you picking up her tab, then why isn't your current gf? I bet at one time you paid for her - at the beginning of the relationship. So why are you griping now? Is it because you don't love her as much? Or perhaps you feel that you already got her, so she isn't worth the effort any longer?
You are lucky right now that you have your financial equal and she pays some. Because I can guarantee you that your next girlfriend will expect you to pay up 100%. Sure these girls on this site say they go 50-50. Bet they have never dated someone making several times more than they do. Even a dumb girl will eventually figure out the math, that because you make so much more than her, you spending a dollar is equal to her spending $5. And that fancy restaurant meal she just paid for, was money she should have spent on her utility bill.
So the cold truth is your career and fortune came with a price tag, and that is women will now COST you. You will pay because three things - you are the guy, because you can afford it, and because women want to be able to boast about what their boyfriends did for them. Just because a woman decided on a successful career does not mean that she agreed to give up these three basic things from a man. Note – your gf is only asking for you to pay for a portion of the fun things/gifts, she isn't asking you to pay for her basic humdrum living expenses. She is looking for the boasting factor so her friends don't think she is a fool stuck with a cheap jerk who doesn't give a rip about her.