Gordon, I have only one Robert Fairbairn from Cockburnspath/Cove in the years you mention. He is the son of Walter Fairbairn c1806 and Elizabeth Anderson c1811 who were married in Cockburnspath 3/10/1827
He was one of at least 10 Children (ages from Census) John c1829 Robert c1832 Grace c1834 Agnes c1836 David c1839 Alexander c1840 Paul c1843 Janet c1845 James c1847 Elizabeth c1850
The appear in the census for Cockburnspath in 1841, 1851 and 1861 (Although by 1861, the four eldest were no longer in the household, fitting nicely with your account).The marriage is on the IGI index.None of the children appear on the IGI which is quite rare for the Fairbairns.They appear to have left the Cove after 1861 as I could not find them in the 1871, 1881 or 1891 censuses.
The only other Robert's I have are: Robert b 14/4/1839 of Robert Fairbairn and Alison Kinghorn Robert c1840 of James Fairbairn and Catherine Allan
I am currently trying to piece together all info I can on the Fairbairns at Cockburnspath if anyone has any more info.