Just been to see my df today. He lives with his partner.
She has recently been diagnosed with a smoking related illness and is on oxygen for 14 hours a day. My dad smokes a pipe.
Her illness is incurable but can still mean a long life.
My dm died a long, painful, horrendous death from smoking related diseases. I watched her deteriorate for ten years.
Obviously this is going to make it a bit of an issue for me, dsis, db etc.
His partner has quit previously (for a couple of years) then restarted again because "life is too short" 
She has been in hospital this year and almost died due to smoking. I went over today and she has started smoking again after not smoking for four months. It was only after she quit I started to take my toddler to their house because it stinks of cigarettes and you couldn't breathe.
I'm 8 months pregnant and have a 22 month old. They building they live in harbours smoke and the smell. I felt physically sick to my stomach whilst there today and I do not want to take my children back there if they are going to continue to smoke.
I would never stop them smoking as it is their house but I equally don't see why I should inflict it on my children.
My dad has said he can no longer get about (I reckon this is half true and half just cba. He's already making excuses that he cba to go to his gd's wedding this year because it's "too much effort") so it's literally take my children to there or he won't see them at all.
Dh doesn't want them going there, and last time I raised the subject about not going there to him, because of the smoking, he gave me a lecture about "crossing the road being just as dangerous blah blah blah weak modern generation". I snapped back saying "my children, my decision" and left it at that. He does like an argument for the sake of an argument.
Aibu to refuse to take the children back there (born or not)? It feels a little bit tit for tat but I'm fed up of bending over backwards for him and her.