They say you can't change a person. I always thought there was one exception, at the beginning of a relationship. My boyfriend smoked when we first started dating. I told him that I will not date a smoker. He stopped.
However two years after living together I found chew in our sink. I asked him if he chewed. He said no. I told him we better call the police because someone broke into our house to spit chew in our sink. He screamed, "I'm addicted!"