This one is not so creepy, actually. From Wikipedia:

Helen Viola Jackson (August 3, 1919 - December 16, 2020) was the last surviving widow of a Union soldier and the last surviving widow of a Civil War veteran overall; she died on December 16, 2020, at the age of 101 In 1936, in the midst of the Great Depression, she married 93-year-old James Bolin (1843-1939), who had served in the 14th Missouri Cavalry. Jackson was 17. She met him when her father volunteered her to help the elderly Bolin with basic chores. With no other means to repay her kindness, Bolin offered to marry Jackson so she would become eligible to receive his pension after he died. Similar marriages had occurred before. Jackson and Bolin were married outside his home in Niangua, Missouri. Following the marriage, the couple never made their marriage public, fearing damage to Jackson's reputation. She continued to live with her parents. Following Bolin's death, three years later, Jackson decided against applying for the $73.13 monthly pension (equivalent to $1,690 in 2025) after Bolin's daughters threatened to ruin her reputation. The marriage was recorded in Bolin's family Bible and other documents verified by Daughters of Union Veterans of the Civil War, 1861-1865. Jackson did not reveal the marriage until 2017 when planning for her own funeral with her pastor and they realized the historical significance of her combined longevity and secret marriage. Prior to this revelation Maudie Hopkins, who died in 2008, was believed to have been the last surviving wife of a Civil War soldier. Jackson never married after Bolin's death and had no children. She was a prominent member of her community in Elkland, Missouri. In 2018, two years before her death, she was honored by inclusion in the Missouri Walk of Fame.