Mighty, this is a long process - the healing. I have been thinking about the Walmart incident and in a way it illustrates what we are dealing with in a nutshell. In the case of OW a damaged and entitled person, who has the mad idea that if she wants something that makes it OK . . . they both are and are not affected by us. They do feel bad, and they feel bad about feeling bad because they are'entitled' right? Urworthy is correct - nothing we say will change what they do, but her reaction was not that of someone who could rise above what what you said to her.
On the contrary it hit home, and fed the drama. And in general it is preferable to starve the drama, but once in a while it doesn't do any harm to rock the boat!
You have a glimpse, if you choose to take it, to see just how unsafe she really feels in this situation. Your xh has already left her once to return to you. You are everything she isn't, and she knows it.
I think MLCers and their chosen companions are emotional idiots. The Good Lord help that child. Your children will be OK - bruised and hurt but not fundamentally damaged, because they can see that what their father did was neither normal nor healthy for him and those around him.
I know you want it to get better, but accept that healing from anything takes time. All I can say that the hurt releases its grip