I agree with everyone who has posted here....nagging him or acting disappointed in him will probably NOT help. I have been an on-and-off smoker since I was 13, and it is HARD to quit -- and whenever anyone "scolds" me about it, it just makes me want to smoke more. The only time I have ever been able to quit for any significant length of time (during my pregnancies, and for 4 years after the last one) is when it was MY decision and other people left me completely alone about it. I can second the Chantix recommendation -- it truly does work like magic. I am getting ready to refill my prescription and give it another try. It worked great for me -- I think my problem was that I did not continue taking it for long enough, and I slipped back into the habit.
But, yes, bottom line is that guilt is not going to help, pressure is not going to help, and -- honestly -- your being involved in something that, in the end, is his personal decision is not going to help. Certainly you have the right to set boundaries for yourself (you must brush your teeth first if you want to kiss me, no smoking around the baby, etc.) but not try to control his behavior. As I have pointed out to my daughter (when she nags me to quit)-- nobody is perfect, and I am not either. Everyone has habits they would like to change, and most people are honestly doing the best they can on any given day. As I pointed out to her: "You know I don't like it when you fight with your sister. Well, just stop." And of course she replied that it's just not that easy -- her sister makes her mad, she has bad days, etc. And so I pointed out the correlation. It's easy to tell someone else to "just stop" THEIR bad habits, but when we look upon our own suddenly it's not so cut and dried. Do YOU have any bad habits? Overeating, gossiping, complaining, or anything like that? What if someone told YOU to "just stop." Would you be able to?
I don't mean to sound hard on you, as it is clear that you love and care about your husband and family and just want the best for them. But the older I get, the more I realize how pointless it is to try to change or manipulate anyone's behavior other than my own. You have a right to tell him how you feel ("I worry about your health") and to set your own boundaries and, ultimately, to leave the relationship if you decide you can no longer tolerate smoking and that it's a deal-breaker. But other than that, it's really his business whether he smokes or not, and the best way to help him is to let him know that you love him no matter what and that you support him when he does decide to quit. His feeling "wrong" or "not good enough" is never going to produce lasting change.
My boyfriend had a bad habit that was driving me crazy, and no matter how much I brought it up it never changed. When I started accepting him unconditionally and focusing on the positive things about him instead of focusing on that one thing I hated, the habit gradually disappeared on its own. I have seen that happen over and over with people -- when you fight something you are giving it energy, and it grows ("what you resist, persists"), and when you stop resisting, dynamics change almost as if by magic.
Good luck to you, and to your husband!!