Every relationship is prostitution????

So I just got back from volleyball practice and let me say it was a WORKOUT!!!! But anyway right now i am supposed to be doing my homework, which i have in like every class. Stupid AP classes. But as you can see I'm blogin instead. Something my English teacher said today kinda "stuck" with me. The teacher is a male so, well, ladies you'll know what i mean... He said that one time he wrote a paper once on how every relationship is prostitution. Yes, i know its kinda mind- boggling for a sec. His point was that a woman wouldn't take a second look at a guy if he didn't spend any money on her. He also said that women tend to be more materialistic, which i sort of agree with him there. But I would rather a guy set up a romantic picnic in the basement then take me to some fancy restaurant if he did it straight from the heart. But that's just me. And so therefore he says its practically the same as a guy walking up to you and paying you $200 dollars just to sleep with you. And i think that most of us would be very insulted. I don't know it's just something to think on. Again feel free to comment.