I have to agree, you handled that conversation very well!
You told her that you did not agree with a D and that she would have to tell the kids which I think is very important.
From what you wrote, your W sounds conflicted to me. I also had the same convo with my W the other night about doing "real work" on the M as in both of us in a concerted effort.
At any rate, I think you were on your game with this one and you need to keep it going!