Yep definately don't talk about, even positive reinforcement in my experience isn't great. The more he feels pressure from you (which can be perceived from positive reinforcement) the harder it will be for him. He really needs to be doing it for himself to be successful. I know from my own experience the more DH winged about my smoking, the more pressure I put on myself to quit, but then it became about him, not me iykwim? Even when I quit (unsuccessfully on a few occassions) DH's 'I'm proud of you' just made it harder because I didn't want to disappoint him and it took the focus away for me. Eventually I would start again, just one here and there, and try and hide it from him. Then over time it would creep back in until it came out in the open and resulted in him being disappointed in me etc.

In my opinion, it's far better to just let him tackle it himself in his own way. If he does end up having one, or buying a packet, I think you're best not to comment. He knows you want him to quit, believe me, but it needs to be him wanting to quit. And if he feels that he's going to disappoint you by relapsing he's probably going to try and hide it, which only leads to more problems in my experience.

Anyway, I hope that makes sense, it is just my personal experience, but I think many other smokers (and ex-smokers) have been in the same boat. BTW I quit when I got pregnant and haven't looked back. Chances are he will get there, but it might take a few more attempts after this one. Hope I haven't been too pessimistic.