This is likely your grandfather. From familysearch.org https://familysearch.org/
You can use their free search tool to find more on this family. Wasn't able to find a marriage record for Jacob Dwight Benjamin and Harriet E Main. Maybe with this information you can connect to the correct Benjamin line. Good Luck.
U S Census, 1880 Preston, New London, CT
self Benjamins M 42 CT
wife Harriet Benjamins F 38 CT
son Charles H. Benjamins M 20 CT
dau Mary E. Benjamins F 15 CT
son Everitt D. Benjamins M 9 CT
US Census, 1900 ED 484 Preston township, New London, CT
https://familysearch.org/pal:/MM9.3.1/TH-267-11931-15373-13?cc=1325221&wc=MMPN-VYD:n186928431
head Jacob D Benjamin M 62 b. July 1838 CT marr 41 yrs
wife Harriet E Benjamin F 59 b. Sept 1841 CT 4 children 3 living
son Everett D Benjamin M 30 b. Oct 1870 CT divorced
dau Nettie B Benjamin F 18 b. June 1882 CT single
U S Census, 1910 Preston, New London, CT
self Harriet E Benjamin F 68y CT widow
son Everett J Benjamin M 39y CT widow
Ella Bogue F 18y CT
U S Census, 1920 New London, CT
self Everet D Benjamin M 49y CT
wife Minnie Benjamin F 29y Minn
son Jared Benjamin M 5y CT
son Morgan Benjamin M 4y7m CT
son Russel Benjamin M 3y6m CT
dau Carrie Benjamin F 1y11m CT
US Census Preston, New London, CT
head Everett D Benjamin M 59 CT
wife Minnie S Benjamin F 39 Minn
son Jerrerd D Benjamin M 16 CT
son Morgan E Benjamin M 14 CT
son Russell S Benjamin M 13 CT
dau Carrie E Benjamin F 12 CT
son Richard L Benjamin M 8 CT
dau Jennie C Benjamin F 6 CT
dau Hester E Benjamin F 4 CT
son Winthrop C Benjamin M 0 CT
U S Census, 1870 Preston, New London, CT
J B Benjamin M 32y CT
Harriet E Benjamin F 28y CT
Charles H Benjamin M 9y CT
Mary E Benjamin F 5y CT
Connecticut, Births and Christenings ? probable Father of Everett
Jacob D Benjamin
birth 12 Jul 1836 PRESTON TWP,NEW LONDON,CT
father Seabury Benjamin mother Lucy
U S Census, 1850 Ledyard, New London, CT (possible wife of Jacob, mother of Everett)
Nathaniel Maine M 31 CT
Mary A Maine F 26 CT
Harriet E Maine F 7 CT
Mary M Maine F 1 CT
