You give and you take in a relationship. Sacrifices are mandatory and each person shapes themselves to each other in the ways that are necessary. Usually that's how it should go.
I smoke because I enjoy it. ENJOY is the keyword here. I take the measures I need to take in order to make my health be "under control". I know it doesn't make me any good however I smoke, I drink and I can live longer than you. You can go outside and get hit by a truck or you can have a subit heart attack. You're never well in life so might as well live it the way I want to and not in the way that society condemns me to.
Measuring someone's personality through one life decision that isn't even permanent seems way off to me. Life will shape you I guess.