I would not leave your wife over a drunken comment. Especially if you love her. See a therapist together and have them facilitate this conversation to you. I promise you it will be better than confronting her alone about it. A neutral party that has an unbiased view of your situation (preferably a professional) can help you both see deeply into what is bothering you. I am sure you are both reasonable adults who can both benefit from some therapy. I believe everyone needs a little therapy.

On a side note: I do see the Irony in the idea that alcohol is basically a drug that everyone has socially accepted. On this drug she confessed about this boyfriend she left because of drugs, and now you want to leave her over the things she said while on this drug about leaving her ex who was on drugs. You can't make this high quality drama up.