The smell will give it away anyway. And if you're concerned with health issues around vaping, wait until you smokes cigs a few years....

But yes, you can tell him. And he can decide if it's a dealbreaker to him.

Being that passive isn't cool tbh. Experiment, try to get in charge, do things. Because yes, he doesn't have a comparison, but looking back he will realise this wasn't great

And yes, trying and experimenting together can be awkward sometimes, funny other times - and incredibly sexy most times. Give it a try.