Thanks everyone, for commenting. So many questions, so little time.
Fearless, I agree that just saying, "I'm going. End of discussion" is a recipe for disaster. I see that I have created a situation that is, depending on how you look at it, a lose-lose proposition, or a gift, an opportunity to talk about both of our issues. I intend to approach it with the latter view in mind. But if push comes to shove, I'm ready to push back. As I've told myself in other situations where I might get ambushed by my W or exW, "hope for the best but prepare for the worst." My little outburst on the phone yesterday happened because I did something I 1)shouldn't have done, and 2) wasn't adequately prepared for: I jumped into the pit with her, stayed too long (shouldn't have done that)and started believing too much of what she was saying about me.

Not that there wasn't some truth to what she says, (e.g. financial imperfections, forgetfulness), just that she has an uncanny ability to focus on the negatives about me, ignore the positives (or just give them lip service) and paint me as some sort of evil, selfish, lazy etc., monster. And that is something I am not.

Yesterday, she came home in a predictably grouchy mood and, at one point, I asked her to tell me what the "distressing news" was she had mentioned the day before, but which I had forgotten to discuss with her upon my return, later that evening. (I had also asked about this during our phone call yesterday morning). She said, in an annoyed tone, that she didn't feel like talking about it right then.

I said, "Okay, I've asked twice now. If you care to share it with me, go ahead. I'm not going to ask about it again."

Little steps, I guess, toward becoming a man who refuses to play the "you didn't ask me the right way at the right time" game.

I'm going to call my friend in Tucson today and talk to him about all of this. He may have some insights, too.

Hairdog