Dear OP: I understand how you feel about being a "gentleman" but the fact is, "old fashioned" raising wasn't about kissing women's asses. It was about respecting them and their needs and opinions but not asking for their approval at every turn.
I know, in this day and age, boys are raised to please women. More and more fathers are absent or deadbeats. Throughout school we're trained to please our teachers, who are almost exclusively women.
So to start your change in attitude, remember that your are NOT under any obligation to make a woman happy. Of course you should be respectful and courteous, but NOT a servant. Women like decision makers, they like men in control of themselves and their environment.
Regarding your current situation, here's how to handle it: When she mentions Chipotle, say "This Chipotle place sounds great! Why don't you invite me there some time?" If she doesn't catch the hint, tell her, "All right, all right, I'm not THAT dense, you want to go to Chipotle with me. How does (day) (time) sound?" When she mentions her ex-boyfriend again, say, "You're gonna have to drop that subject if you want another boyfriend, cause I haven't heard of ANY guy who likes hearing about ex-boyfriends." If she shuts up immediately about her ex, she's into you. If she doesn't, it means she doesn't care about pleasing you, which means she's not into you (or insecure, or crazy. Neither of these are good traits)