Hi.
One of the most frustrating things in the world is watching someone you care about do something potentially destructive and not being able to do anything about it.
If you have discussed this with him in an angry, critical voice in the past, you might change your approach. People tend to rebel when confronted this way, even if they themselves have considered what's being suggested.
Try softening your tone and letting him know that you are afraid because you really, really love him and want him to be around for a long time. Tell him that you're scared that you will lose him. Sometimes a sincere, emotionally-honest approach is best.
You could also try giving him coupons for nicotine patches or other anti-smoking products, but he is more likely to appreciate the gesture if he's already thinking about quitting.
Ultimately, the decision is his. Don't take it personally if he doesn't give up smoking right away. Nicotine addictions can be quite powerful and his smoking is in no way an indication of how much he loves you.
Take care.
