It's good to vent (not in a medium subject to legal discovery).

Of course if you do want to communicate things to her in writing you should go ahead and assume her attorney will be reading it in court... so you want it to be absolutely factual, calm, non-inflammatory, yet direct and specific. Like Ghada's version. But work in "best interest of the children" somewhere in there too. So then her attorney will never read it because it won't be useful to them. Even then there are pitfalls, but life is full of risks. IMHO, YMMV.