I see your points...in replaying the conversation in my head, I did not do much validation of her reason for wanting the D. I don't do that out of fear...fear that if I don't tell her how I feel about her and that I still want the M, that she will think I don't care and proceed with the D much quicker.
In my mind, to validate her decision for the D tells her that I want a D too. Or that I'm not interested in saving the M. Since I don't want her to think that, I go to the opposite extreme and tell her how much I don't want a D. In doing that, I make it about me and my feelings.