Your family tree:
http://trees.ancestry.com/tree/16265208/person/2063142029Hubert Walter Monger, born 7 May 1918, died 16 Oct 1998 in Umatilla, Oregon (Source Oregon Death Index). Marriage to Unknown 12 Sep 1985 in Carson City, Nevada. A Hubert Walter Monger, born 7 May 1918, Albany, Alameda Co, CA, died 16 Oct 1998 in Hermiston, Umatilla County, OR. He was married in 1936 to an Adeline A. Cherrington (born 5 March 1919 in Utah, died Nov 1984 in Henderson, Clark Co, NV) in Oakland, CA in 1936. They had three children (per a family tree owned by Lavinia Phillips: Lyle Anthony "Butch" MOnger, b: 8 Apr 1942 in Albany, Alameda Co, CA.
--One of your first leads would be to obtain the obituaries of Hubert and Adeline. The obits "might" identify where John/Hugh was at the time and possibly the name of his wife.
The Reno Evening Gazette, 12 oct 1943:
In the Second Judicial District Court of the State of Nevada, in and for the County of Washoe: Hugh Walter Monger Plaintiff, vs Adeline Louise Monger, Defendant. Summons: The State of Nevada Sends Greetings to the Said Defendant. You are hereby summoned to appear within te ndays after the service upon you of this summons...
--There is no proof these are the same person, but likely. It would then appear they stayed married if Hugh John was born in 1945.
Father of (From message posted on Ontario, Canada board ?)
John Hugh Monger, born Hugh John Monger, 1945, in Nevada. "kept in touch with his last two sons because my mother in law stayed married to him for 19 to 20 years." WHO is the Mother-in-law ? Have you "interviewed" her to obtain as much info as she has? He was married to "Susan Marie Hegler and Debbie Dee Eberle.
The California Birth Index shows a Hugh John Monger born 23 June 1945 in Stanislaus County, mother's maiden name Charrington.
--So, he was born in California, not Nevada.
The California Marriage Index: Hugh J. Monger, born about 1946, marriage to Sandra M. Paiva, 10 Feb 1968 in Alameda Co.
--The Reno Evening Gazette 6 March 1971
In the Second Judicial District Court... Sandra Monger, Plaintiff, vs. John Monger, Defendant.
California Divorce Index:
John H. Monger, 45(year of birth), Susan M. Hegler, 45(year of birth), 75(year married), 12/75(Preliminary Dissolution) 1(type) 01(county) 473478(case number) 151860(State file number)
--This indicates they were married in 1975 and dissolution 1975.
--This case was in Alameda County.
Nevada Marriage Index:
Debbie Dee Eberle, resident of Nevada, marriage to John H. Monger, resident of Nevada, on 24 August 1979 in Clark County.
--The CA Birth Index shows a Debra D. Eberle, born 15 April 1956 in LA County, CA, mother's maiden name: Armstron. There is NO proof this is the correct person.
While it is highly unlikely you'd find either woman in the online telephone directories, I looked anyway (I don't reference if it doesn't have the information). Their names of Hegler and Eberle were found, but no way to determine if any was the correct person. Their first name with Monger was checked. But, I would "assume" both have married since 1975.
I would suggest contact of the County Auditor Recorder in those counties of marriage and the COunty Superior Court (or Judicial District Court) to obtain a copy of the divorce decree.