When do you push to hard?

With cigarette prices to go up tomorrow, I have been trying to get Scott to stop smoking. Maybe I am emotional right now cause all the hormones, but I love my husband and I would love for him to stop smoking. He keeps promising me that he is going to quit but I know he is still smoking. Last year I made him a doctor's appointment to see about getting chantix. He tried though he really didn't want to quit. Then I got pregnant, and we made a promise that he would quit smoking and I would eat better cause I have gestational diabetes. He started again taking his chantix, and had quit for a little over a month. Then I was having some problems with the pregnancy, and that gave him a excuse to smoke. He says it calms him down, which I know that is another excuse... So since February he is been sneaking around smoking. Every time I find some cigarettes, lighters, or light fuild I throw them out. I know it's the pregnancy that makes me do it lol... I hate that he lies to me. If he doesn't want to quit why doesn't he say so. He needs to quit. So I have called the doctors office again today to get him some more chantix. He is going to stop. I feel like one way or another I will make him see that he needs to stop, not for me, but for his kids. I want to be able to spend the rest of my life with him, and I don't want him to die like my granny did cause she could of lived longer if she had put down the cigarettes. Scott need some motivation. He is going to be 60 years old living on a oxygen tank and still smoking. I don't want that. How can I make him see... I have to keep pushing harder and harder.