My wife never smokes her own, as she says it's too much for her, but she steals puffs from mine all the time. Her love for tobacco really started back in France, where people smoked cigarettes everywhere. Back when we were first married, she enjoyed the smell of tobacco every great once in a while as it reminded her of her time in France, and I was only smoking once or twice a year then.
She thought it was fun that a couple times a year her brother and I would hang out and smoke a cigar, and she's been happy that I have something I really enjoy. I think her real endorsement of the hobby came last summer, though. We spent many warm summer evenings in the hammock after the kids were asleep, me smoking a cigar and her laying next to me, taking occasional puffs, just chatting and sharing our thoughts and dreams and ideas. That time spent together was really wonderful. As I've become more of an enthusiast, she's grown with me. She actually has a remarkable palate, and is often able to identify flavors I'm struggling to label.
The only thing she dislikes is the stale smoke smell, so if I've been in the garage, or at a lounge, I come in through the garage and throw all my clothes into the washing machine before entering the house, and generally go shower from there.