Telling the kids that their parents are separating is gut wrenching. Especially if the kids dont take it too well. I still remember having to pick my son off the floor when he broke down upon hearing the news. And I remember the feelings of contempt I had for my wife for causing emotional grief upon our children.
The best thing you can do is be your daughters rock right now. They need someone stable in this difficult part of their young lives. They will remember how their dad faired during this terrible time.
Have you considered what to do when your W next gets reassigned?