Sobriety. Fucking. Sucks. - Ozzy Osbourne.
I wonder how much of your issue can be attributed to isolation. It's interesting that you managed to stop drinking when you were married, and managed to stay away from it for so long, but have an issue now. Maybe the issue isn't so much sobriety, but boredom.
I definitely get how sobriety can be a bit boring at times, but I find being in a satisfying relationship with my wife interesting enough that I don't really need alcohol or drugs lately. But a number of months ago she went away with our son for a couple days and it didn't take long before I reached for some of my whisky out of boredom. Similarly, last winter the doldrums got bad enough that I started experimenting with CBD oil and edibles. But once summer hit and I could get outside I didn't feel as much of a need.
Well, it seems I am only bored when I'm sober, and that I become interested in things only when I'm under the influence of something
That's kind of what I'm getting at, at this point in your life alcohol is the only thing occupying your time. If you had other outlets like satisfying relationships, hobbies, work etc you wouldn't need to turn to alcohol as much.