My boyfriend promised and he broke it

So when I was getting to know my boyfriend (we’re both 17) everyone knew him as this guy addicted to weed, I’ve never really liked that or wanted that quality in a guy (not against weed, just think we’re young plus it’s ilegal where I live) well he said he’ll stop, just because he didn’t like the image it left him and for me, he really likes me and didn’t want that to be a problem. Well today he came to my house but it was evident he had smoked before he came, when I asked what was wrong he lied so I confronted him because he was a little high in front of my mom & I just don’t like that at all, I don’t want my mom to think bad about him (she’s very strict with that). He then confessed and said he had a fight with his mom that’s why he did it, i cried because i was just disappointed, I couldn’t even speak to him, I was just lost for words, he told me he was extremely sorry, that he didn’t want to see me cry. Well to finish this off, I feel stupid for crying over that but I just couldn’t help it. What do you guys think?