C., you have received some good advice here, and I'll be repeating some of it. I think you really need to hear it. This is coming from someone who has a husband who dips, has quit, has started again, wants to quit, and struggles.
I am not LDS, but I did grow up in the SL Valley and have a very firm understanding of your faith. Yes, you can go to your bishop, and, yes, he can essentially take care of scolding your husband for you. Putting on the restrictions, etc. But rest assured that if you do that your husband is only going to resent you more and it's going to cause more problems for your marriage right now. Before even considering this, calmly talk to your husband.
As has been stated, nicotine is EXTREMELY addictive. Your husband can't just walk away after the Temple Blessing simply because his physical body says he can't. Part of the addiction is a hold on the brain, as well. Honestly, Christ understands and is willing to forgive, despite this being against anybody's religious beliefs. It takes time, it takes willingness on your husband's part, and (maybe most importantly) it takes understanding on your part. Nagging and confronting him makes him feel like you're attacking him. Like you feel he's less of a man, not someone you WANT to be with. He's only reacting as anyone who is constantly bugged about a bad habit is.
The best thing for the both of you right now is to sit him down and not get upset. Apologize for your nagging, let him know you're concerned about his health. If you feel you need to remind him of the covenants of your faith, then POLITELY do so. Ask him if he would like to go to the bishop for help (remember, I said don't turn him in...it'll cause a whole lot more problems at home). Ask him if he'd like to find some methods to try and help break this addiction. If, at this time, he says no, don't sweat it. He's understandably sensitive because of your arguments. He has to want to make the first step or it won't do any good. Be patient, be understanding, be supportive. This is going to take time, and you making it well aware that you completely disagree with his addiction and pushing will only serve to make him do it more.
Please don't freak out. I know it's difficult, but it will make things better. Rest assured other Mormons are in your position, though some are struggling with alcohol or some other addiction, so you are NOT alone. You'll be okay, just take a breath, keep praying, and be supportive. Breaking addictions are never easy, and they take time.