Maybe the fathers name on the marriage certificate was wrong.

. Could he have been Jean Baptiste Aubert aka Baptiste Aubert
There is a Leonie Aubert born Grouville on the 1871 / 1881 census with parents Baptiste & Marie. Also there is a baptism mention on FindMyPast for the period 20 Jul 1861 to 26 Feb 1871 for a Leonie Adele Aubert at Grouville though no finer details are given just a link to Jerripedia.
1891 census has a Lena Aubert as a servant to John Coutanche - RG12/4696 f71 page 4 - In 1891 Baptiste & Marie appear on census but only their son Baptiste is at home.