Great thought and insight before me. It sounds like you handled the situation very well...staying calm, not flying into anger/fear. The Naranon literature states that the very thing that an addict wants the most from us is anger and fear.
Boundaries.....I'm one to try and respond to this - ha ha. It's been a long slow road for me. I am definitely not a quick study. However, I have learned to only make boundaries that I am willing to back up with consequences....if you do such and such then I will do such and such. It really doesn't matter so much what I am going to do as it does that I will 100% do what I said that I would do. Thus...the importance of only making boundaries that I am willing to back up with my actions. My RAH knows that if he should use crack in or out of the house that he will no longer live here. There is no question in my mind about what I would do. I know longer worry about (much) whether he is going to use or not because I know what I will do. I'm not saying that I would end the relationship at that point - only that we would not live together. I would support him if he chose inpt rehab/recovery and remain in his life to see what happened. I'd make new boundaries as I needed depending upon the circumstances. Just because that is what I would do is not any comment on what you should do. Maybe you say....if you use in our home I will no longer interact with you for the next week - or - I'm going to fix liver and onions every night for a month. See....it only matters that you set a boundary that you are willing to live with....there is no right or wrong because it is such an individual thing. You will discover the right boundaries for you in time.
Remember.....you can't change anyone or anything....the only thing that you can change is yourself. If you change then people can change for themselves to accommodate (or not) to your changes. At least that is what I've found to be true for me.
Alanon/Naranon and working the steps have helped me so much. My RAH has said the same things at time about "his business" being spread around. My response is "you're the last person that I talk about at meetings....I'm there for me and my life - not yours".
Hang in there! Donna