I know that when I was in my darker days of codependency but trying to find a better way to live, distracting myself from the obsession was a good start. Making myself do something, anything that took my mind to a better place, gave me a reprieve from the obsession at least for a while.
I found that I cherished those moments. Finding an hour of peace, then a half day, then a whole day where I took my mind back to focusing on myself and my happiness, gave me a new clarity of what life could be, if I was willing to let it.
Meetings helped me more than anything, not just for the meetings themselves which helped me find a better path, but I made friends there, friends I could trust and who understood. We went to dinner and a movie once a week, and often met for coffee or a walk in nature, and those get togethers helped me see that life didn't have to be all about my addict son, that it could be better if I did what I needed to do to get out of myself.
It's like being stuck in the mud. We don't like where we are but our feet just won't go anyplace else. Sometimes we just need to take off our shoes and step out. Who knew?
There is hope for you. You clearly see that he is bringing nothing to this relationship and it sounds like you are tired of doing all the work and yet not changing the outcome.
When you get sick and tired of being sick and tired, and it sounds like you're there, it's time to try something else, it's time for change and change begins and ends with us. We can't change them but we can say "enough" and step out of our shoes to find a new path.
Hugs