Thought I'd forage around for you and see if I could find anything of help.
1881 Census, William Gosen born Canada, aged 36 B 1845, Lodging in Glamorgan Wales with the Boulton Family. Status as married. Occupation General Labourer
1881 Census Amelia J Gosen born Alderney aged 28 B 1853, Children Caroline (7), William (6) Agnes (2) and Elizabeth Gosen (11 mths)
It was not uncommon for husband and wife to be living apart at times. I've found it on a few of my ancestral records. It was usually for work purposes and they were not far from one another.
I think William Gosen must have died sometime after 1882 (Youngest child George born in 1882) and prior to 1891 but can locate no death or burial notice on Free BMD or Ancestry UK
1891 Census in Wales, Amelia is with Richard Saunders. Her children Agnes and Elizabeth who were 'Gosen' on the 1881 Census are now named Saunders. (When they marry they are Gosen's so most likely a transcript error naming them as Saunders on that Census)
*on Free BMD the surname is Saunders rather than Sanders which appears on the 1891 Census
William Gosen is living with them and is still Gosen. Caroline Gosen is a servant elsewhere in Wales at the time of this Census. (Caroline's place of birth on the 1891 Census is given as Portsmouth Hampshire although the 1881 states Bedwelty Wales)
There is another child George Saunders Born 1882 on the 1891 Census.
From Free BMD (4 children born in Bedwelty Monmouthshire and 1 Merthyr Tydfil)
William Frederick Gosen Born Q2 1875 Bedwelty
Louisa Mabel Gosen Born Q1 1877 Bedwelty Died Q2 1878 Bedwelty
Agnes Gosen Born Q3 1878 Bedwelty
Elizabeth Gosen Born Q3 1880 Bedwelty
George Edward Gosen Born Q2 1882 Merthyr Tydfil
I could not find the birth on Free BMD of Caroline Gosen who was born in 1874
Amelia Jane Gosen married Richard Saunders Q4 1896 Bedwelty Monmouthshire
Amelia Jane Saunders nee Gosen Died Q1 1900 Pontypridd District aged 46 years
I have searched far and wide for the marriage of Amelia Holman to William Gosen. I was not able to find either on the 1871 Census, infact the 1881 Census is the only Census where I've found William Gosen.
Could they have met in Canada and married there? Or possibly in Hampshire (where eldest child Caroline was born in 1874)
Marriages (All per Free BMD)
Caroline Gosen - no information on her after 1891 Census
William Frederick Gosen - Did not marry (Still single at 1911 Census)
He Died Q4 1918 Pontypridd District aged 43 years
Agnes Gosen married David Roach Q3 1898 Pontypridd District
Elizabeth Gosen married Joseph Hodges Q3 1906 Pontypridd District
George Edward Gosen married Blodwen May Harris Q4 1906 Pontypridd District
Useful link on Gosen's in Wales Section for cross reference
http://www.rootschat.com/forum/index.php/topic,353768.0.html