Re: would you
I think this is the whole problem..that the person may otherwise be a good person with one bad habit and you might lose a good person because he/she smokes. 
Although, I am personally really against smoking.
Re: would you
Get married first lol
Don’t worry yourself about hypothetical scenarios that might never happen. Most of the smokers I know acquired started smoking during their teen years. You’d have to be really unlucky for your partner to pick up that habit so late in life (late 20s).
Re: would you
Well it is not a big deal for me. I have had friends who smoked, my father and uncles did as well. Some left and other continued. I have a very close relative who had lung cancer and he never smoked. Then I had those who smoked heavily but nothing happened to them so it is fine for me. Yes it can cause health issues but so does other things. I would give it a pass to be honest.
Re: would you
Nah. I can’t stand the smell nor want my kids to be exposed to that.