As an ex smoker, you will often get an itch for a fag. It's up to you if you scratch that itch or not. I've not had a fag for years, but sometimes i'll pass a smoker in the street, and think how nice it would be to have one. The temptation will always be there, but i choose to ignore it.
It is more difficult for you, as you live with a smoker, but it gets easier every day that passes.