WOW Jen. You got a lot going on girl. Listen...something that kept ringing out to me as I read everything you wrote...and you seem to come to it at the end a bit...DETACHMENT! Worrying about another bomb is your own insecurity. If he leaves, he leaves. You can't control that. And you should know by now that you will be ok without him anyway. Right? I know you worked hard to get where you are right now...but it is not about winning or losing it is about what is right for YOU. That doesn't mean stick by him but it means stop worrying about losing after putting in so much effort.
As for the smoking thing....I dunno. Glad he's quiting. You know a M is a like a see saw - expect him to be down for a bit and expect to have to be up for a bit. Hopefully, he'll be able to do it and come back up and feel better than ever and then...if you need to be down...he can be up for you.
As for the intamacy thing. Nothing is more attractive than a strong, independent, detached woman. SO...see my first paragraph again.
Your good Jen...I just feel like you have gotten to wrapped up in him and your M and you are starting to lose YOU a bit. Go find you. Once you have that...all else will fall into place.