How Robert finds out,maybe.
Henry: honey, I hyded the kid
Robert: 'I hided the'?- WHAT HAPPENED TO OUR CHILD.
Or alternatively,
*nynx And edward do a crime™ and they run into Robert running away*
robert: .... Who is this child
Edward: your one
Robert:......... Are we SURE she isn't a combo nation of our dna?
That sounds about right, yes.