I'm so proud of you. For letting go lovingly. For knowing you can't "fix" him and resisting the urge to try. For working toward forgiveness. For letting him take responsibility for his own life and mess he made of it. For getting on with your wonderful life.
Many people MUST learn the hard way. This is his journey and as hard as it may be to see him suffer, it is the only chance he has for getting his life turned around. I hope, for the sake of your children he finds the strength.
In the mean time keep doing what you're doing with your life--thrive and be well. Write this chapter of your life in a way that will help those of us, your adoring readers, see your strength and courage and resolve.