Now that I know I'm becoming a doormat, how do I fix this?

Just ask him some time when you're alone. Don't get accusatory, just ask. He may have good reasons (or at least, reasons so you can understand). He may not know you would really like to be treated to dinner and movies and things. I have a friend who never treats ever and when I asked, was told "you'll never see me picking up the tab ever, I'll pay my share but not anyone else's" because that was the way the father did things. Your situation bothers you a lot since you've continued to pursue this, so just ask him what's up with going dutch on everything. At least if you know he's aware that you'd sometimes like to be treated, you know it's not just oversight on his part. And if he has a reason for not doing it, even if it's just an ethical thing ("well, women want equal rights so that should include paying for themselves"), at least you'll know not to expect him to treat ever.