You two have been together for 7 months now, he really loves you and accepts you the way you are, but he hates when he's being controlled, when you two argue about him smoking he gets really mad and frustrated. Of course you didn't want to control him, you just knew that he's really destroying his own health with smoking so much. And now he got so frustrated that he didn't even realize what he's saying, he mentioned your insecurity, your body.