For me, it's a turn-off if a guy insists on paying for everything. I like to pay my own way. I also like to be the one who gets to treat sometimes, it makes me feel good. In particular, it's the INSISTING on paying that gets to be a turn-off for me. It reminds me of this one guy a few years ago, we had a date at his place which was on a slightly dodgy road, he said "let me call you a cab", I said "no, that's fine, I'm happy to walk", he's all "no, you have to take a cab" I'm like "I spent two years living around here, I'm quite comfortable walking" and then he actually starts to call a cab. I just walked out.
Or, in short, I think it's a good sign that the OP's date has now started letting her pay! Insisting on paying when your date specifically says that they'd like to do so is not polite.