Samuel Billings married Mary Foote sometime after 1763 but before 1778:

Groton Land Records
17 Mar 1763:
Mary Foot, wife of Ebenezer Foot of Groton, bought land from Richard Williams of Groton. (Vol. 9, pg. 56)

31 Mar 1778:
Samuel and Mary Billings sold land to Samuel Affrice. This is the same land that Mary bought from Richard Williams. (Vol. 9, pg. 49).