A woman in my Alanon group who just passed away a few weeks ago had spent her life married to an active alcoholic. Like Amy mentioned, she was an elderly housewife and had grown up in that generation where you stayed married no matter what.
Alanon helped her cope with her situation, and to detach from her alcoholic husband. The principles she learned allowed her to fill her life with hobbies she enjoyed and friends who made her happy. When her husband started "pushing buttons", she went down to the basement and worked on her craft projects. She probably spent 75% of her time down in that basement hiding from her husband. I loved her dearly, but her shares always made me so sad.
What really struck me about your post is that he bragged to you about knowing how to manipulate his ex and said he was still "figuring you out." That honestly made me sick. I don't think all alcoholics are that deliberate about emotional abuse and manipulation. It really sounds like he has other issues besides just the drinking and even if he sobered up he would still have a long way to go to become a decent human being.
You are doing the right thing going nc with this guy and it sounds like you handled yourself well during you unexpected encounter with him. Stay strong and keep up the good work. Hugs.