Under Gloucestershire, England, Extracted Parish Records on Anc*try there is a marriage recorded for a Richard David Murch and Elizabeth Bryant 24 May 1835. Assuming this is the correct couple and given their ages in the 1841 census and the mixture of children in the household I suspect they were both widowed at the time. This info is from a transcript so you would want to see the original for yourself to clarify this and see what other info is included. Witnesses can be very helpful clues. The original image does not appear to be online. Collection: Gloucestershire: Bristol - Register of Marriages 1800 to 1837.
Having said that, be aware that relationships are not given for households in the 1841 census. However, George Bryant is listed as son-in-law to Richard Murch in the 1851 census but is single. This terminalogy was often used at that time to describe a stepson.
If this is the correct couple and Elizabeth was widowed, there is the possibility her maiden name was Lloyd but you would need to determine this through further research.
PB
