Should i break up?

it's been 2 years since I've been dating this guy and I made it very clear in the start that I will never marry a smoker. he agreed but recently he has started smoking. He doesn't do it very often, maybe thrice a week but it's enough to understand that he is addicted, although he won't admit it. I personally am so against smoking coz I've seen how 1 persons smoking habits have destroyed the health of an entire family and I cannot let that happen to my family.

I however decided to compromise and asked him if he can promise me that his smoking will remain at this level (thrice a week) and no more than that. And he could not promise me that.

I don't date without the intention of marriage and I can't marry a smoker, so should I break up? Hes an amazing boyfriend otherwise. It just hurts me that smoking is more important to him than having me by his side.