here it is then...either it's ok for you to smoke out, and she doesn't break up with you or bitch at you, or it's not ok for you to smoke and she gets to leave you.

you can't say, it's ok but I'm going to give you hell every time I see you.
that's not cool, and it makes you not want to be around the person. Either she needs to accept you for who you are, or move on, no point in staying around and making you both miserable. Talk to her, tell her this shit, tell her it bothers you and your thinking maybe your not as compatible as you used to be. People change, and you can grow together or apart, but don't cling to something just because it's familiar.