OK, first things first, I can't remember how readily available the book "Divorce Remedy" is, in Aus. You should be able to order it on Amazon. Definitely get a copy and read it, as it is really the basis of how we support each other on this forum, of course.
As far as journaling, yes. Just keep posting in this thread, as Cadet said, up to 100 (total; incl. responses) posts in the thread, then start a new thread. Even if it's just thoughts from the day. It can be very helpful to let stuff out.
So the two of your have had some fairly major issues. What do you think has kept the two of you together for 18 years?
As far as her fears that things will revert, those are certainly valid. I'd guess that you would not want things to just keep being the same, either.
That said, you may start to hear a lot of the familiar "script" that most will hear. Like "we got married too young" or "I never loved you" or "I feel I missed out on life"... oh, right... you've already heard that last one. It is interesting how common the language that so many of us hear.
At the top of this forum (newcomers) on this board, there is a thread called "Sandi's rules". Read them and stick to them as best you can.
What do you think some of your W's valid complaints about you, might be?