Catharine was William's second wife, but this FAG entry is the source for the following info (citing The Lightner Heritage, by Steve Bast, published 2006):
Elizabeth Roby did not marry William Lightner. Instead, she married George Wood, according to a marriage bond dated Dec. 15, 1820 in Pendleton County, Virginia. [This doesn't make a convincing argument, as the marriages are a good 2 generations apart, and there obviously could have been more than one Elizabeth Roby - however, consulting the book (which does not appear to be available online as of Jan 2025) might make the argument more clear.]