WARNING: There is a lot of conflicting information about Sarah's identity. Her maiden name is in dispute. Her birth date is unknown.

FROM TRACER FAG #48125332, 7 Mar 2018:
Freeman Genealogy : Freeman, Frederick in three parts, Viz : I Memorial of Edmund Freeman of Sandwich
Under 4th generation, pages 32 & 33 discuss a letter from a Miss Julia Moulton of Mansfield in 1854, a descent of Skiffe Freeman b. 1723 son of Edmund Freeman b. 1683 "My father says the Skiffs, formerly of Windham, were cousins to us; Edmund born 1655 married Sarah Skiffe."

FROM CHRISTOPHERC FAG #49077762, 29 Nov 2019:
Please note: the Sarah Skiffe born in 1646 at Sandwich to James and Mary Skiffe is NOT this Sarah... whose last name at birth was almost certainly not Skiffe/Skiff. My ancestress Sarah Skiffe is the woman born in 1646; she married Thomas Mayhew (III) about 1673, and the pair had children between that time and about 1686. Sarah died at Chilmark in 1740. _The maiden surname of the wife of Edmund/Edmond Freeman is NOT known_. It was (barely) listed in Torrey's "New England Marriages Prior to 1700" as "[?SHIFF]"; later, in the 1800s, an elderly relative -- confusing generations -- stated that the Freemans were cousins to the Skiffs of Windham, CT... and opined that Sarah "Skiff" was Edmund's wife. The Sarah Freeman buried at Sandwich in 1742 should properly be shown as Sarah (Unknown) Freeman. For details, please see my whole string of sidebar comments on the WikiTree profile for Sarah Freeman at wikitree (dot) com/wiki/Skiffe-15 . Thanks, Christopher

FROM JEANINE LAWRENCE:
NEHGS has several records in their databases that specify Sarah Mayo as Edmund's spouse. The records are from seven different people who applied to be added as Mayflower descendants. 
#1: General Society of Mayflower Descendants Membership Applications, 1620-1920; Vol. Brewster, William, pg. 4807:3
#2: General Society of Mayflower Descendants Membership Applications, 1620-1920; Vol. Brewster, William, pg. 4816:3
#3: General Society of Mayflower Descendants Membership Applications, 1620-1920; Vol. Brewster, William, pg. 4958:3
#4: General Society of Mayflower Descendants Membership Applications, 1620-1920; Vol. Brewster, William, pg. 5035:3
#5: General Society of Mayflower Descendants Membership Applications, 1620-1920; Vol. Brewster, William, pg. 5077:3
#6: General Society of Mayflower Descendants Membership Applications, 1620-1920; Vol. Brewster, William, pg. 5144:1
#7: General Society of Mayflower Descendants Membership Applications, 1620-1920; Vol. Brewster, William, pg. 5265:3
#8: Mayflower Families Fifth Generation Descendants, 1700-1880: Vol. Hopkins, Stephen (Vol 6), pg. 189
#9: Mayflower Families Fifth Generation Descendants, 1700-1880: Vol. Brewster, William (MFIP Patience), pg. 75
#10: Mayflower Families Fifth Generation Descendants, 1700-1880: Vol. Rogers, Thomas  (Vol 19), pg. 144
I found a birth record in one of their files for a  Sarah Mayo, born Dec 12, 1660 in Boston, MA, to Samuel and Thomasin Mayo. The date coincides with Edmund's birth date of 1657.
The citation for her birth: Citation Boston, MA: Births, Baptisms, Marriages, and Deaths, 1630-1699. (Online database. AmericanAncestors.org, New England Historic Genealogical Society, 2015.) Originally published as: A Report of the Record Commissioners of the City of Boston Containing Boston Births, Baptisms, Marriages, and Deaths, 1630-1699, Rockwell and Churchill, City Printers, Boston, Massachusetts, 1883. https://www.americanancestors.org/DB1646/i/30233/167/52536420, Vol. Boston, pg. 74