Hello and welcome to you. I was really touched by your story, I am so sorry for the many difficult situations you have been through. I applaud you for your self-awareness and desire to do things differently this time.
I really like what you said about focussing on you and your life and improvements in that area. That is really all you can do right now. But what does that mean for your relationship with David? It is so hard with love in the mix, I hear how much you want to help and support him, I do. But you also do to deserve to suffer and be afraid.
If I were you, and had grown and wisened up like you see to have, I would get out now. I would do so with love and care, but would do so. I know how overwhelming, sad and difficult that will be but in my opinion it is the best thing for YOU. You know the old saying "start as you mean to go on". In other words I would put my foot down now, before this escalates further, and make clear you are unwilling to be with him if he does not make his recovery- from alcoholism, sex addiction and the emotional stuff that comes with that- a top priority in his life. You will also not stand for him lashing out in anger at you. All couples have disagreements, but you should not have to deal with rage fuelled blow ups and have to live in fear of how far things might go. The more you let this go on the more you set the standard of what you are willing to put up with, thus, start as you mean to go on. Make that firm stance now before things get even worse. And, who knows if they even will get worse, maybe they won't escalate like other situations you have experienced in the past. But you never know and the surefire way to prevent it is by being clear and firm that you will not allow it and taking actions that show that if things do not improve.
You are not asking him to build you a castle or to have a face replacement so his looks suit you better... What you are asking is not selfish, you are asking for something that makes your home life more peaceful, your relationship happier and importantly, asking for something that will be very beneficial to HIM.
But again, the most important part here is that your actions must back up your words. I would be very strong right now, very, very firm. Either get help David or I am leaving. Then do it, as hard as it may be considering how much you love him.
So very sorry for what you are going through. We are here for you anytime you need to reach out.