He left me because I am causing him anxiety

Long story short. Unfortunately for me I used to be in a 10 year relationship with a binge drinker that completely destroyed me. 5 years laters I started a relationship with an ex although I knew he was alcohol dependent. I tried to ingonre it and keep it all light and take its slow to see whether there was anyway for us to be together. During our time together he started being of very low mood and we didn't meet cause he was getting sick and was depressed. I think most of his physical problems rise from alcohol or are certainly worsen. Ofcourse he denies any problem. All medical problems are because of bad dna. After I discussed with him, he got anxiety and his health deteriorated. No matter what I tried I was at fault, if i discussed I was pressuring, if I stayed quiet I did not now how to communicate. Ofcourse his behaviour was perfect, and I am just unreasonable when he is low. He finally told me he cannot be with me cause I am causing him anxiety which affects his physical health. Firstly he hurt me deeply as I truly love him (probably forever). The mental hoops I had to jump to try to think how we could work when I know there is an alcohol problem. Then although I have been there before, I go through the mental torture of thinking, perhaps it was not this bad and it was all in my head, and perhaps with my worry I destroyed one of the most important relationships of my life. And when I say with my worry I mean literally just my internal thoughts, because on the outside my worst sin was to stay quiet as I did not know what to say besides the obvious; you need to quit.