"Maybe get through the pregnancy and newborn stage together then tackle the quitting when baby is a bit older and hopefully sleeping well etc?" By which point babies health could well be already affected by dads smoking!
No - he's better doing it now before he's also dealing with sleep deprivation and needing to support a post Partum mum and newborn (without putting them further at risk).
I'm another who wouldn't even date a smoker, it's an utterly disgusting habit and I don't understand anyone under 50 even having started smoking! Given by the time they were old enough to it was well knowing how unhealthy it is.
We're now STARTING to understand that even tertiary smoking is harmful. I would not be at all surprised to learn this is a major factor in SIDS too.
Op ask him 'do you really want your baby's health affected right from the start? For them to have anything but the best opportunity for a healthy home?'
I hope he doesn't smoke in the house any more at least.
For me the difference between this and him drinking, eating things pregnant women are advised not to etc is that we KNOW it has a direct effect on others around a smoker.
It DOESN'T just affect the smoker.
Honestly the sooner this vile habit becomes a thing of the past the better.
"at a midwife appintment she tested really high on the co2 test, like almost 4%, which was equivalent to her being a daily moderate smoker!" This might be an idea - a midwife appointment when he can attend to and this test be done - it's unlikely your result would equate to that of a mother in a non smoking household and midwife could maybe have a word too!
"Don't be ridiculous. Yes of course it'd be selfish of the DC to expect him to quit just because they don't like it." Wow! How about because they don't want to develop asthma or emphysema? Or cancer? Would that be ok?!