In case Chase doesn't respond, here are my two cents.
Arabs have a saying: "He who eats my food heeds my word." It's a variation of the "he who pays the piper calls the tune" adage, but food here is more appropriate to your case.
What you're saying is that you have responsibility towards her, but without the authority that usually comes with it. There's a word for guys like that: suckers. And while she might take advantage of such a guy, she won't respect him or even feel that much sexual attract towards him for it.
If you're gonna provide for a girl, or for anyone for that matter, then you're gonna have some decisional power over that girl. And that definitely includes, "No you're not going to that party tonight."
Responsibility goes hand in hand with authority, and the more of the former you have the more of the latter you should have.