ok, well the first "for instance what if..." that springs to mind is, what if Parent A did try to give up smoking, or started to only smoke outside, but Parent B continued to smoke in the house and tell Parent A that he/she was being stupid, believing scaremongering and so on? It's damn near impossible to give up smoking while living with a smoker. That would make Parent B extremely selfish, stubborn, whatever you like, but Parent A no worse than lacking in self-esteem and willpower, and trust me that's only too common in relationships. Then add in whatever extraneous circumstances you like... I remember a friend of mine, had severe depression (in and out of mental health services), was a smoker, then a close relative died, and she asked her doctor for advice on stopping smoking and the doctor advised that, while it was a very good idea generally, she'd prefer my friend to wait a month or two for things to settle before attempting it as it may cause too much stress for her, in her situation, and with her family support being upset themselves, to deal with. Of course the couple in question may have had none of this. My point is simply that we don't know and we shouldn't judge.