Caught S/O smoking weed outside

Yesterday I came home from the grocery store and walked up to my s/o outside sitting in his truck and he turned and looked at me dropped a lighter and had eyes redder than a tomato. I suspected he was doing this, but didn't want to accuse. I know people are so relaxed about weed smoking these days, but I don't want him doing this and being around our 3 month old. It's still illegal and it's still a drug and I don't want her growing up thinking if her dad does it then it's okay. He knows I don't like it and has been lying about it and when I confronted him after he came upstairs he just told me "it's legal in 4 states, it's not a big deal" mind you we live in Florida, it's only legal for medical purposes, not recreational. Can someone give me some insight here because he has me second guessing how I should feel about this and I just want to be a good parent and set a good example for my daughter