+1 on Dan ariely and social norms. Sorry but what if genders reversed doesn't work for me. Genders aren't on level playing fields in dating, if a woman spends 4 years on a relationship that goes nowhere, that's a large chunk of her fertile/dating time. To put in market terms, most men will contribute more financially, so he should upgrade accordingly.
I'm female and a math/logic geek so I also had a hard time accepting it when guys wanted to pay for dates. One time, we were both grad students and not only did the guy research an interesting outing (rare!) and drive, but he then sensed my discomfort with the friends/dating line and backed way off on the ride home. (I heard later he was pretty smitten and was worried he'd overplayed). I was trying to drop my share of the food bill accidentally in his car. That's not my $20, I have no idea where that came from. Not to be rude or make it less of a date, but its the kind of reciprocity I was raised with. At the same time, he refused to let me fake drop the money, because yeah. The final result is less interesting to me than the nudges every step, that both of us are tripping over ourselves to give more. I know the alternative - staying home, hanging with other people - is less enjoyable to me and I'm happy to bring my resources to bear. Another night maybe I would have paid the tip or came up with a theater outing and cooked dinner or suggested we take public transportation because parking is ridiculous. If I had a car and he didn't, I'd drive. It's not because I'm spineless or a feminist, I've been in strict 50/50 situations and your idea/ you pay situations.
But pretty much every time a social relationship works out, I notice that we both feel like we've gotten the better end of the deal. We both feel like we should give more (but accept the others generosity). In this case, it feels like the bf should pay extra /charge nothing for op to live with him, since 1. He will probably get a cleaner house, better (cheaper) dinner, and certainly more sex that way. 2. If he wants to charge market rate, he better expect to live with a slob who has male visitors stay overnight and runs off with the juice maker when she leaves. That is, if you want a roommate off craigslist, be prepared for a roommate off Craigslist. If he wants a less serious dating relationship, he should be prepared to drive to her apartment or job, take her out for dinner/theater/movie, stay at her place or drive her back to her apartment in the morning. I assume his dating bill will drop by at least $900/ month because living together is now acceptable for dinner to be pizza and movie to be a cheap DVD and a beer to be $1 instead of $8.