Need help

My boyfriend is sweet and he’s a good guy and he’s never mad and he’s just a good person. But the thing is, he jokes allllll the time and I don’t mean jokes like knock knock I mean jokes. For example, today he was talking about how vaping is killing a bunch of people and he’s thinking about smoking cigarettes. Not to offend anyone but I HATE cigarettes. Absolutely hate them and he knows that. I get sick being around it and rn we are trying for a baby. So I of course flipped my lid and said “no that’s not happening” and he said it’s not my decision to make. Long story short he said he was joking and that I always take him serious. In all honesty I do because I can’t tell the difference between sarcasm and serious. How do I stop taking everything so serious? I feel like it’s my fault. 🤦🏻‍♀️I’m 19 and hes 22 so I try to be mature about things but that really flipped my lid. Advice?