Welcome and its great that you have come out of hiding. I really don't have any experience about exit counselling but do with counselling in general. In my offline life I am a qualified social worker in Australia (but dont tell everyone its a secret!) With counselling in general it usually is of more benefit if the person themselves seeks the help. They have to want it to help. Basically counselling does not give you the answers but helps an individual explore the answers that they already have in their possesion but just don't realise it. Its an independent, non-judgemental ear for the person to bounce their thoughts, ideas and explore their own answers.
I think time is going to help heal your children and yourself. They sound old enough to be able to seek help for themselves. Is this something they have asked you to help with or is this something you feel you need to do for them? That's a rehtorical (sp?) question for you to answer to yourself. If you feel you need to do this for them but they have not requested it, it might not be overly helpful. They sound like adults so let them make thier own minds up and you be guided by their decision. If they ask for help, then seek it. Of course its up to you!