What are her issues? Has she discussed what has led her to feel this way? I'm sorry if you stated it before but I've forgotten. Is she willing to talk about it? How are you holding up? When will the kids find out?
I think I would have great difficulty divorcing and being friends with my ex wife. I would prefer to turn all the assets into cash and go our separate ways. You situation is not so straight forward because of the ages of you children. Hang in there buddy, your not dead yet.