Is my quitting smoking coming between us?

My wife and I are trying to live cleaner lives and have been trying to quit smoking. I have had better success than her. The problem is more the smell and smokers breath now. I love her dearly, but the smell is now a nuisance, where it once wasn't a bother. I am trying to help her but need to do it in a sensitive and constructive way. How can I tell her she smells? Any Advice?