Stop kicking yourself, hd. You didn't bring this up this morning because that was a bad time and you knew it! Holy cow-- waking her up with this convo when you're both on your way out the door. You're telling yourself you chickened out because you're a chicken. Well, you may be a chicken, but that's not why you chickened out this morning! It simply was not the right time for this announcement.
I am absolutely positive that when the time is right, you will speak up. The words will just fly out of your mouth and you'll be wondering who that is talking and making so much g.d. sense.