Richard Parkinson Sedgwick  [John Sidgwick / Alice Wilkinson]
b. October 26, 1886, England
d. June 9, 1961
m1 abt 1907,2 Jessie Miriam Williamson
m2 abt 1910,2 Cynthia May Willey
m3 Lena B (Cox) Butler

Jessie Miriam Williamson  [D H Williamson, Jessie Unknown]
b. abt 1886, Iowa2
m1 Unknown Black1 m2 abt 19072, Richard Parkinson Sedgwick

Cynthia May Willey  [Levi Willey / Mary Lucenda Washburn]2
b. abt 1888, Mount Union, Henry, Iowa2

Census records:
1900 CO Weld, Grover
1910 CO Weld, Grover
1920 WY Park
1940 ID Canyon, Caldwell
Wife Cynthia May (Willey) Sedgwick
1900 IA Henry, Tippecanoe Twp
1930 IA Henry, Center
1940 IA Henry, Mt Pleasant

At the 1910 census, Richard was widowed and living with his parents, and reported as widowed, but his estranged wife Miriam and a son were living not far away with her parents.

A family tree exists at Ancestry.com which shows one Cynthia Maye Willey b. February 16, 1887 who married Unknown Sedgwick to be the daughter of Levi Willey (1855 - 1916) and Mary Lucenda Washburn (1861 - 1925), both born Iowa. I subsequently found her with them in the 1900 census, linked above.

There is no indication that Cynthia May Willey was married before Richard, so based on the 1911-1912 birth of daughter Dorothy M, I assume that Richard and Cynthia were married in late 1910 or early 1911.

Children of Richard Parkinson Sedgwick and Jessie Miriam Williamson:

Robert Sedgwick
  b. abt 1908, [Grover, Weld,] Colorado2

Children of Richard Parkinson Sedgwick and Cynthia May Willey:

Dorothy M Sedgwick
  b. abt 1911, Colorado2
Marjorie G Sedgwick
  b. abt 1917, Colorado2
Delpheus Richard Sedgwick
  b. November 14, 1921, Newcastle, Weston, Wyoming2,4
  d. January 5, 2005, Multnomah County, Oregon5

Sources:

1. Records of descendant/researcher of this family:
a. Clara Wilson, granddaughter of John's son Anthony
    her source of much of the data is the Vivian A Travis book listed below.

2. Census records, any of those indicated.

3. Descendants of Anthony and Alice (Sayer) Wilkinson
by Vivian A Travis, 1978, pages 47 - 58, copy sent by Clara Wilson.

4. Iowa, World War II Bonus Case Files, 1947-1954
an Ancestry.com database

5. Oregon, Death Index, 1898-2008
an Ancestry.com database