My guess was right. "18 when she married 81-year-old Union Civil War veteran".

Civil War vets had pretty good benefits, which would continue with their dependents. Some married for those benefits.

A few spouses of Civil War vets lived until the 2000s. https://en.wikipedia.org/wiki/American_Civil_War_widows_who_...

That link includes a picture of John and Gertrude Janeway.

based on your wikipedia link, james bolin (93) and Helen Viola Jackson (17) marriage in 1936 surpassed 63 age year gap. so guinnessworldrecord is inaccurate?

Good catch, and yes, it would seem so.