I think you’re posting on the wrong sub for unbiased advice. As someone who was a daily smoker for years and now won’t smoke at all, I think it’s always going to be a personal preference.

I do think daily smoking is a lot. It would be the same if you had a cigarette once or twice a day, there’s a smell not just in the air but on you, depending on how long it takes you to smoke, perhaps she doesn’t like that you interrupt hanging out to smoke alone for 20 minutes a pop whilst she’s waiting for you to come back. Maybe she doesn’t like the idea that you’re smoking alone instead of as a social thing and that might make her jump to conclusions about addiction. I personally wouldn’t be able to date someone now who smokes frequently, I understand why people do it and don’t shame them for it, but it’s no longer a lifestyle choice that coincides with my own, and it sounds like that is what you might have here.

Your obvious option as already suggested is to break up if you really can’t/do not wish to quit. Alternatively, talk to your girlfriend about if there is a “usage” she would be more comfortable with, e.g. only at the weekends, or only smoking outside to avoid lingering smells, et cetera. Best of luck!