My fiance won't stop vaping and we are ttc. Should I wait to try until he stops? I don't want an unhealthy baby

Ps.

There are not a lot of studies surrounding the long term effects of vaping. Also, there is a lack of studies on vaping while ttc or during pregnancy whatsoever. Studies really have focused on the effects of nicotine or cigarettes on sperm and egg quality, but I'm not sure how to apply that to my situation as vape contain far less harmful chemicals than cigarettes. I also vape 6mg nicotine, but have decided to quit to up my chances of conceiving..that's when he didn't seem to keen on the idea which is why I decided to ask on here for opinions.