Finding Matilda's presumed partner Thomas Gellen/Gelling is a challenge. The only clues are the two eldest children's marriages of 1886 and 1887. The father is identified as Thomas Gelling, Market Man, in one and Thomas Gellin, Dyer, in the other. It doesn't appear that he married Matilda and I'm not sure he'll be the father of the other two children born after the 1871 census. The birth certificates will answer that.
The best candidate that I can find is Thomas Gelling baptized 2 Apr 1833 Malew s/o William Gelling and Elizabeth (Betsey) Callow md 5 Apr 1823 Braddan. In 1841 he's age 8 living with stepfather John Bridson and mother Elizabeth + siblings and half-siblings in Ballavodden Malew. In 1851 he's an 18 year old farm labourer at Ballavodden.
In 1861 he's on the "Miranda" Vessels at Sea, Royal Navy: Thomas GALLING, AB [Able Bodied] Single 28, b "Mallew I of Man".
Can't find him in 1871, perhaps at sea? In 1881 he's at Crossack Malew "Half Brother Married 45 Pensioner b Malew" with John Bridson 37 Overseer of Lumber Works, plus the words "dye paint".
Married 24 Dec 1885 age 52 "Widower, Naval Pensioner", at St Thomas Douglas, father William Gelling (deceased) Labourer, to Jane Callow.age 50 Widow, boarding house keeper father Paul Callow (deceased) Gardener.
1891 age 58 General Labourer in Douglas with Jane 55 and a niece.
By 1901 he emphasizes his Royal Navy experience and is with Wife #3. Thomas Gelling, 68 Retired Quartermaster RN and Mary J Gelling 44. She was Mary Jane Cowley, they married 1899.
He was buried age 75 11 Oct 1908 Braddan.
I'll keep checking to see if he stays as the best candidate. One problem is that he married wife #2 before Matilda died, but maybe that's ok if they never married.