I looked at it from the other side and tried to find another couple that would fit the Richard and Martha who married in 1872. However I couldn't find a Martha Crook pre1872 or the couple in 1881. I can't see an obvious Paul Jenkins either - an unusual name at the time - but he could have died.
I did find a Rich Jenkins in 1881 that would be about the right age for the marriage that I keep coming back to and will mention it just in case it is any use.
In 1881 he was listed as Rich Jenkins born 1829 Pontypool Monmouthshire. He is listed as a coal miner as married but is not living with a wife and is lodging the Rowlands and Waters family
https://familysearch.org/pal:/MM9.1.1/XQ36-61C and in 1891 census is listed as an uncle of the family and widowed. Can't see this Richard Jenkins pre 1881
Good Luck Kay
Edit - I see there is a tree on Anc that lists Richard as born 1850 with father Thomas - living in Newland Glos in 1871, however the same Richard is still living with his family in 1881 in Newland listed as unmarried. He dies possibly in 1881.
I sometimes think our ancestors are laughing at us trying to work out who they were
