Leigh, it is time to sit down and seriously think about what you really want.
Do you want to continue in this marriage limbo? If you do then you will have to accept what your husband is doing and live a half life.
Do you want a comfortable, emotionally healthy life for yourself and your children, with a chance for happiness?
If that is what you wnat then it is time for a final break.
Let him know that you've waited as long as you can for him to "find" himself and you are going ahead with your life without him. If you can't tell him to his face, because he will only tell you he just needs more time, then write a letter. Either way, once you've made the decision, stick to it.
He is out of your life and that leaves you free to become who you want to be and to make a better life for yourself.
I still maintain he needs counseling.
Good luck, Leigh. Keep us updated.