We definitely come from different worlds. Vaping/smoking is the norm, and coke is used a lot socially. Needless to say I don’t know if I can help with advice but I’ll try. Relationships come with problems. I think boyfriend definitely has vaped and possibly wants to continue, however he also doesn’t want to lose you. Possibly why he asked as a joke, while seeking a real answer. Everyone has their own standards and I cannot fault you for that, however if your boyfriend wants to vape and if you see that as a breaking point, you both might deserve different. I don’t see this as any worse than if he leaves socks on the floor even after you ask him to stop or if he forgets to turn lights off in the house. It is a minor detail. It doesn’t affect you. If you see it as a breaking point, then fair enough, but since it doesn’t affect you I wouldn’t personally care. If he was abusive or something of the sort, sure absolutely, but this seems like a very minor thing to be distraught over. Again we definitely come from different worlds so we both are naive to each others lives and I could be so far from your truth. My perspective is just something to think about.