Huge Thank you! To everybody who replied.
@FallenAngelina
We are professionally involved and this was also the way we got to know each other. We were working together for a couple of years and a couple of months ago he started hitting on me (I guess because some love story he had ended and so he was looking for a new girl). First I only midly laughed about his attempts to score with me and I am that kind of girl who goes out with such guys and set things straight with them. Usually I am not interested in such guys and they lose interest in me when they understand how I function. This time it was different and it was me who got interested. Getting to know each other on a private level was a whole different story and initially I developed a crush on him (see my old post).
I have never gotten that close with an addict (although I know enough people around me who had/have addiction problems) and knowing back then what I know now would have helped me a lot.
Anyway, he knows that his addictions badly affects the people surrounding him, he is well aware of how much harm he caused to people he loved and he feels a lot of guilt and shame about that. Because he has this experience (which do not have) he realized what he was going to do to me so he started to back off. I can give you examples: He stopped messaging about private things (only if it is about our job), no private meetings (after work yes but no making up just to meet privately), respecting my boundaries (like not calling me drunk) and so on. A short time later he stopped drinking.
At the beginning it made me angry and upset but later (and after coming to this place and learning a lot) I am grateful for it.