<human>: Provide a brief overview of the text.

My boyfriend of 6 months is/was a recreational pot smoker. I am uncomfortable with him doing it (for personal reasons, not *just because* I don't like it), but never made a big deal of it until he did it in front of me. After that, I tried to explain calmly and rationally about why it upset me, without getting mad at him or telling him what to do, and he apologized profusely and said that if it bothered me, he wouldn't do it.

We went to a going-away party for one of his brothers, and his brother asked him to come outside and light up. I was in the same room, but there were probably about 10 other people and we weren't focused on each other. He declined, and his brother scoffed "That's the first time I've ever seen you turn that down". Later that night when we were talking alone and he was expressing how upset he was that his brother was leaving, and how he wanted to hang out with him. He ALSO mentioned his brother wanted to smoke up with him, and that he "didn't want to". I left early so he would be able to see his brother for a bit before he left.

I trust him when it comes to everything else, but I'm not sure about this. It's just not a big deal to him. I've made it clear how it makes me feel without accusing him of any wrongdoing, but I'm worried he'll do it and won't tell me, and I'd really like him to be honest with me about things that affect me. How should I approach him?
<bot>: I'm afraid my boyfriend may be smoking pot behind my back, and I'd really like an honest answer from him. I'm afraid he might hide it out of fear of upsetting me.