Sounds like you have every right to put the foot down in a tactful sort of way. One or two a week smoked outside is in no way detrimental to your health. In fact, it's probably beneficial if you can do it without worrying about the wife nagging you every time you light up.

If it's the smell.. maybe change your shirt before you come in the house if possible, brush your teeth directly. Try to find a remote corner of the property where you can relax, and designate it as the smoking area. If she enters that area, it's at her own risk. Relationships are all about compromise, and it sounds like she needs to be reminded of that. Is there a chance she's resentful that you have a relaxing hobby and she does not?