This marriage to Phebe Case is probably a second marriage for Samuel, since his son Rufus was born c 1773 (RI Cemetery Database). Samuel's will dated 8 June 1813 WG, proved 27 Sep 1813, mentions his wife Phebe; sons Rufus, Amon, Jonathan, James, & Daniel: daughters Ruth Whitman, Ase Mires, Martha Potter, Sarah Kinyon, & Tabitha Case.
I have very roughly estimated the birth years of Samuel's children mentioned in his will, specifically those by his first wife.