Bad smoking habits

However, just recently a couple of months ago he tells me he wants to start vaping..? He knows I hate smoking, not good for you not good for anything whatsoever! We are TTC, and I've already voiced to him that vaping will be just as horrible as smoking again. He promises me that it doesn't have nicotine in the ones that he buys. He even showed me the receipt showing that one of the flavor doesn't have nicotine. He promises that the rest he bought from the side that doesn't have nicotine in it... however the bottle labels still show that there's a possibility of nicotine.. sigh. 

I want to trust him and he has told me he's not wanting to get addicted to nicotine again, but I don't know. The habit was so hard for him to quit and after 8 years of being clean, here he is from the random blue he's vaping... I'm more worried about the thought of him being addicted to a habit that's not good for both our health. Especially if we are TTC. We've discussed it, but every time I bring the thought of bad habits and getting addicted again he tells me to drop it... 

Maybe I'm overreacting but I love him too much to just not worry about these little things that may turn into a big bad habit.. 

In addition to this before he started vaping our sex life was pretty good, but it has now dropped down to nothing..the other day he even had trouble staying up.. which has never happened before. We have talked but it's now come to the point where I want to stop TTC.. I'm bottling all this emotion inside and it's making me so depressed. 

Am I in the wrong for overthinking.. sigh..