As someone who grew up surrounded by smokers but who never ever had the urge to take it up myself I feel very very strongly about this. As a small child I absolutely detested being in smokey environments, yet I constantly was, at work, at home, with my friends, through no choice of my own, because I was in the minority and no-one gave a thought for what I needed in order to be comfortable/happy. I used to beg my mum to let me open the car windows because I felt so sick and she'd say no because it was too cold!
Even if you are not actually smoking, the permanent build-up of tobacco smell on your breath is utterly nauseating, and contrary to popular belief held by many smokers, it doesn't go away just because you suck a mint or clean your teeth - it's an all-enveloping smell that comes through your nose, and your pores 24 hours a day. You would have to go without cigarettes for days before it would go away. You just realise it because you have become desensitised to it. Most non-smokers can stand next to people in supermarket queues and tell you whether they smoke or not.
My DH gave up smoking when he met me, (20 years ago) but over the years he has gone through phases of being an occasional social smoker. He is having one of those phases at the moment. He thought he could hide it from me, but of course it didn't work, and once he realised I knew, there seemed little point in being so careful, which has led to him smoking more often, more openly. The kids have found out which means he has completely lost any credibility when lecturing them about the risks of smoking.
Even though he is currently smoking probably fewer than 20 a week, and never in front of me, I can still smell it on his breath and his skin when he is sleeping next to me, as it builds up, and it revolts me. It is causing us a few problems TBH as I don't want to cuddle or kiss him, but he just thinks I'm being controlling, and laying it on thick to make a point.
TBH I'm past caring about the principle, past caring about the health risks - his lungs and heart, not mine, but I can't get past the bloody disgusting taste/smell. Not sexy.
But at least I have a choice - a baby who is held close and smothered in horrible breath has no choice.