That last line: "I love him enough to let him go and find the happiness he didn't find with me. "
Seeking, I know that is how you feel. And it is great that you are able to reach the stage of the process. I too feel much the same way. But I like to think of it a bit differently. "I love him enough to let him go and find the happiness he turned away from with me."
You were never the cause of his unhappiness. Just a convenient scapegoat, as most of us are. I have no doubt that you have wonderful, loving memories of your married life. He has them too, albeit buried behind a wall of his own self-regard. But like JUMANJI-remember that movie?- it won't stay ignored forever. The drums will start to pound in the back of his mind, and those memories will leak out. What he does with them remains to be seen. Happy Anniversery, Seeking. You keep the memories of today you want to keep. Buy yourself a bouquet and go bike riding in the park. Something for you, alone. (((HUGS)))