Hubby sneaking cigarettes....

Advice sought. My DH who smoked a long time...25 years...quit beginning of this year. I think the stress of new baby caused a weak moment and I've smelled smoke and noticed he would kiss my hand instead. Love him so much but his health and our baby are critically important. I tried to confront when I smelled it last and just encouraged him to let me know if he's struggling. He denied it and that's what hurts. Any suggestions? I hate smoking, and I'm also an ex smoker...so I know the challenge especially after a few drinks.