I very much think you are right about the socializing more as a couple outweighing the concerns. In time she might come to see that her being rude to you in public is only making her look bad then, maybe she will reevaluate her actions.
Maybe your W sees quitting smoking as more stress than she can't handle right now. What she fails to realize is that even if she had permanent damage it will escalate to a much higher level with less that could be fixed.
Are there support programs in your area for smoking cessation. I feel you are right in that it is easier than doing the work.
JAK
You don't get to choose how you're going to die. Or when, you can only decide how you're going to live now. ~Joan Baez