What an awful position to be in. It's very hard sometimes, I've been in a relationship with a dope smoker before and I had to be very honest with myself and him. In the end I ended it as I had a problem with the smoking and knew that I always would have a problem with it. He was a lovely person, but his habit was not. I think that once you are talking about what to do that deep down you know and have already made the decision but need verification so to speak from others. Whatever decision you make I'm sure will be right as it sounds like you are thinking very much about your children. All the best with it.