Twinflame,
Don't make things harder than they have to be on yourself and on your husband.
You've already successfully left the WBTS with your children. They're grown and gone. Your husband has accepted it and keeps on trucking. It seems that he's left you alone; then, what is it you're looking for? Leave him alone! Don't sweat the small stuff anymore!
Doing some volunteer work is a step in the right direction. Fill your life with positive, constructive things and live it one day at a time.
Otherwise, it all just sounds to me like you want out and are looking for an excuse. There's no perfect situation/relationship out there, you know. Find enjoyment in the life you have now and quit the whining.
DY