I agree with you Peter T. If I fell in love with someone who enriched my life, the smoking thing would be of little insignificance. Though, caring deeply for this man would generate concern about his long term health and I would probably make that gently known.

I was in a relationship with someone who was on heavy medications for Attention Deficit Disorder (ADD). The 'cocktail' of drugs he was taking had many side-effects and I was concerned about his liver. Over the 3 years we were together, he gradually weaned himself off the medications and though we are not together anymore, I know he has maintained being drug free.
I never nagged. The change came about from genuine concern and being in a supportive relations.

Bonnie