hi there,
it is very unlikely that their marriage cert would have any parents names on it i'm afraid. - this didnt become compulsory until 1855.
i have a marriage in Inverness in Nov 1837 and it is typical of entries around this period; it reads:
Fletcher: John Fletcher seaman and Isabella Fraser same place both in this parish by the Rev Robt Macpherson
another on the same page reads:
Mackenzie: Roderick Mackenzie farmer Knockbain Ross Shire and Mary Fraser Merkinch Inverness by the Rev Alexr Clark
i have looked at several others from the same area pre 1855 and none have parents names on them.... sorry to disappoint
the best way to find their parents would probably be to find their death certs (assuming it was after 1855) and the parents names should, if known, be listed there...
scotlandspeople do have 1 match (death records) for a Margaret Matheson other surnames Robertson aged 72 in 1888 in Inverness, Inverness. - i have not viewed the actual cert though so cannot be sure if it is definitely the correct person. if it is the correct match though, it would also help narrow down the date of death for her husband, i.e whether she was a widow when she died or not.
sorry i could not be of more help.
kind regards,
Lorna.