Isn't it amazing how just getting the thoughts into concrete words and onto (cyber) paper can make you feel instantly a little better... I love that aspect of this bb.
Anyway... He may or may not have been thinking of her... and I agree it is best that you did not press this with him... don't want to open that can up.
You know you can't control his thoughts... and would you want to if you could... really??? He is with you and you are seeing and experiencing forward movement and slow healing. I may be naive in my thoughts, since my SO is in contact with exow and really makes no bones about it... knows it hurts me sometimes. Anyway.... what if you try to look at his passing thought of her in the midst of an oncomming huricane as just being a compassionate human being. Wouldn't you rather build a life with someone that has the capacity for compassion and concern for the well being of another being?
Please don't take my words as a way to negate your feelings... believe me when I say I understand the desire for the exow to just vanish without a trace. But if you can allow him the strength to love you and build a life with you while still caring for others (even others that you might not feel deserve it)... it might help to solidify the love that you feel for him and the love he does show you is real. Make any sense at all??