Maybe he is conscious that if he is all over her people will think it is fake? I know this is Peter Andre we are talking about, but I'm tying to think of a reason. My partner and I are very affectionate but I can't imagine being a total cuddle monster when being filmed.
And maybe compare her with a certain person as well?
I think she is quite reserved as a person and she is still getting used to having a camera crew record her. I know I wouldn't be as hands on with my man if a camera crew where following us around all day