It is my opinion that they do not show sadness in public because that will put into question their decision and they don't want someone trying to talk them out of it. Also knowing that your are there as plan b is comforting to them in case it doesn't work out. Remember that how they feel now is how they think they are always going to feel. Just as they believe that you are always going to feel the way you do now. We both obviously know that feelings change.
