Most of you know my mother-in-law moved in with us about three months ago as my father-in-law passed away 11 months ago and my MIL was not coping well on her own. I love my MIL dearly and she and I have a very good relationship. However a serious issue has arisen and I'm not sure how to deal with it.

My MIL has always been a very heavy smoker and in fact had a lung removed about 8 years ago due to lung cancer. Despite that health scare she has not quit. My hubby and I have never allowed smoking in our home. I'm allergic to cigarette smoke and my son is a severe asthmatic (we're talking Intensive Care hospitalization kind of asthma).

When we first made the offer for her to come and live with us we very clearly explained that there was still no smoking in the house and that she would need to take that into consideration. This was something we were not willing to bend on. She said she needed to quit anyway and this was a good reason. She managed to quit for 10 days. It started with her going outside for a cigarette here and there but has escalated to her smoking all day in the house while we're at work/son at school and then opening the windows for a bit before we get home to try and disguise the smell.

When you're a non smoker you can tell instantly when you walk in that someone has been smoking. Plus it's cold out now and I have the furnace running and she's opening the windows - flushing the heating dollars right into the great outdoors.

Today when we came home the house completely stunk of smoke and it was actually hazy inside. When I said "whoa, it's really stinky in here, you know there's no smoking in the house, right" my MIL commented that she didn't smell anything. My hubby looked at her and said "please Mom, we know you've been smoking in the house. It's obvious". She then looked me right in the eye and said "it must have been Iain's friends". My son iain has two friends who smoke but they have NEVER smoked in the house and have been incredibly respectful of this rule. i was taken aback by the bold faced lie. My husband reminded her that she could go outside for her cigarette or if too cold, could smoke in the garage.

When we were speaking a bit between the two of us later, my husband began to sympathize with my MIL stating that she has smoked for 60 years and it's an addiction. I do understand that and we have offered to get her help to quit on three occasions since she has moved in. I know this is difficult for her but I'm constantly stuffed up now and my son is back on his puffers for his asthma. We're talking health issues here.

Anyone have any suggestions on how to deal with this? I'm also concerned that this could become a problem between my husband and I if he starts to feel sorry for her smoking outside. I'm afraid this is one rule I'm unwilling to bend.