Working On It...
This is a difficult one...I think that what ever you decide to do with this situation, you will maintain your quit. I think this is true simply because you have asked the question. If you did not have the desire to achieve cessation, it most likely would not have occurred to you to do so...Good for you...
Now down to the nitty gritty of it...I can only speak to you from my own experience and my experience is not yours, and yours is not mine, but I believe there must be some commonality.
Until I was a full year quit, I would not allow myself to go to a bar, have a social drink or engage in activity that would soften my will to make cessation a reality. I knew from my research that alcohol has a chemical and social affinity to nicotine. So any type of socialization that included even the smell of alcohol was banned from my agenda. All my life I had always been a very social animal. I had many friends who I dearly loved. However, most of them would not or could not understand my desire to drain the poisons from my body. So I decided that I would make a change and without explanation, simply vanished from my circle of friends until I knew beyond knowing that I was strong enough to live along side my past.
I only tell you this, so that you will know that I took a very severe route to cessation. Stoicism can be a very good tool, but it does not substitute for the very human desire for companionship. It sounds as if you see something of interest in this person and if that is the case, you owe it to yourself to follow your instincts. But if you feel in anyway that being in proximity to cigarettes will weaken your will to succeed, then it is best to run in the other direction as fast as you are able.
I think that avoidance of triggers is the best action. In time you will find that those triggers have no power, but that time comes only when you know beyond knowing that you have truly taken their power away. Perhaps you will find that this individual also wishes to "put the squares down"...It may even become a future source of shared purpose with your new friend...But for now you must protect your quit at all cost...Perhaps you might explain this...You may find that this person will see you as quite a serious person and may be encouraged to seek the same freedom that you do...
stay well
nonic
So we didn't even have to get divorced over my decision to quit smoking. Whew! And as you personally know, that inner rebel will not be phased by evangelical naggie negative reinforecemnet anyway - at least it sure the heck doesn't work on my hubby! (tried it; not good results; backed off!) 
