I don’t know anymore

My boyfriend smokes weed and I don’t like it and I told him that if he wouldn’t stop I’d leave him because my family is known for drug addiction and my dad died that way and so I don’t want it in my life and like a month ago he lied to me and I had a video someone sent me of him doing it and he lied and I was crying saying why are you lying and we took a break after that then he just did it again and lied I’m not even mad at the fact he did I’m mad he lied and I told him last time that was the last chance yes people are human they mess up I just don’t know what to do and he doesn’t tell me oh it’s not a big deal he says I’m sorry I’m sorry and I’m like no no then why did you do it so ugh idk man any advice