http://www.ppe-agency.com/500px/Jan2010/PPE10012759.jpgI'm not sure about the decorations on the front of Mary's dress. What were they? In my opinion they looked a little awkward.
CP Mary is wearing the royal family order (QM's portrait with the white and red bow) and a diamond brooch which belonged to Prince Henrik's mother.
Joachim is beaming with his beautiful wife on his arm. The way he always extends his arm to her is so gallant, I think. Frederick could take a lesson from his younger brother.
Why should he? The Crown Prince Couple are obviously comfortable as they are and don't feel the need to hang on to each other all of the time. All couples are different.
Just because they are not arm in arm, doesn't mean that CP Frederik was not equally as proud or beaming at his wife as well, as this photo shows
However, depending on the situation, there are occassions when the Crown Prince Couple are 'arm-in-arm', e.g. the gala dinner for COP 15, the New Year Gala dinner and even at the Court Ball as well!
http://www.ppe-agency.com/500px/Jan2010/PPE10010118.jpg New Year gala
http://www.ppe-agency.com/500px/Jan2010/PPE10012799.jpg Court Ball