Husband occasionally smoking

So I’ve been happily married to him for quite a few years and he has kept from me that he smokes sometimes when he’s stressed. Not regularly but once awhile. When I found out he told me he’d give it up but I can see it’s not always easy to follow through. We’ve been TTC #1 for awhile now and I’d like to help him give it up completely not just from the conceiving angle but also for his health in that long run. Has anyone been in a similar boat and how can I help him?💛