Do you have any more information to go on?? Also is there a profile link or URL to his profile on WikiTree that we could check out? Sometimes their attached relatives may show up on a census report along with them, or a Find A Grave Memorial page may have relatives etc.
Found two possiblities: a Sarah Long, and then a Sarah Hicks:
*Virginia, Marriages, 1740-1850 Birth, Marriage & Death Name Alexander B. Davidson Spouse Sarah Long Marriage 23 Mar 1838 - Augusta, Virginia
*Pennsylvania, Death Certificates, 1906-1963 BIRTH, MARRIAGE & DEATH View Image NAME: Alexander Davidson SPOUSE: Sarah Hicks BIRTH: location