Stoner boyfriend?

Ok so my boyfriend smokes every once or twice a week and I’ve told him in the past that it doesn’t bother me at all that he smokes, but the thing is, my parents don’t know that he smokes, and I know they’re totally against it... I’m kind of scared of telling them. Also, don’t really like how his car smells, because I get serious headaches, I’ve told him before, but he just laughs it off.. I don’t want to be in his car one day and get off smelling like that..I honestly don’t know what to do.. since I’ve told him before about these things, and especially being stoned while we’re on a date or even hanging out, because I don’t think he should be high just to have a good time with me.. please help!!!