Don't your kids deserve a sane home with a happy mama? Is it necessarily in their best interest to live through this rollercoaster?
As for not knowing how much longer you can wait for him to grown up and be an adult,...what says that you have to wait a specific period of time? There is nothing forcing you to wait X days or X months, hoping and praying that your AH finally steps into the partnership.
IMO, you have ever right to give yourself some space and time to heal. Just because you separate physically doesn't mean the marriage is over, and it doesn't mean you can't reconcile later on, when you are ready and willing to do so. Right now, from an outsider's point of view, you don't seem to be getting much out of the partnership, and I wonder what your children are getting out it too.