Telling her MYOB or asking why she's interested will definitely put her on the spot. My W's standard response to this was "I'm just curious. If you don't want to tell me, fine. I don't care, do what you want."
Depending on how detached you are, the above could be a blow to your PMA or could boost it.
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Me: 39/W: 37 D13-D11-S8 M/T 14/20
EA confirmed: 9/13/07 D-Bomb: 9/19/07 OM Gone since 12/18/07 W wants to fix marriage: 3/16/07