Im guessing that she didn't start going out with him then think "I'm gonna start smoking today, while I'm at it I'll get a couple of dogs too"
If the dogs were there when he came on the scene then he has to accept that their wellbeing is part and parcel of the chores of the house.
Secondly if he doesn't like the smoking he shouldn't have starting dating a smoker - not expect her to drop an extremely addictive habit for his benefit.
Obviously people SHOULD stop smoking, but do it for their own health and finances, not so he can have nicer snogs.