Same situation, kind of. I smoked when I started dating my gf, but have since quit. She hasn't. It doesn't affect our relationship really, but it bother me because of health reasons. If it grosses you out or something to that degree then that's going to have to be your call. If you can deal with it, then I say go with it and just express your concern for her health. If she's quit now, tell her to not stop. After three days the nicotines out of your system, so it's all in you head from there. But if she does smoke and you can deal, just go with it. I don't think it's something to end a relationship unless you can't be around it because it bothers your breathing or you don't wanna kiss her or something like that.
bash, bang, slam, whatever, yeah, ima drummer.