Conversation so far:
What was Wallis Simpson's relationship with Edward VIII?
In January 1934, while Lady Furness was away in New York City, Wallis Simpson allegedly became Prince Edward's mistress.
Were Wallis Simpson and Edward VIII romantically involved?
Edward denied this to his father, despite his staff seeing them in bed together as well as evidence of a physical sexual act.
When did Wallis Simpson and Edward VIII marry?
Edward VIII married Wallis Simpson in France on 3 June 1937, after her second divorce became final. Later that year, the couple toured Germany.
How did Wallis Simpson and Earl Spencer meet?
In April 1916, Wallis Simpson met Earl Winfield Spencer Jr., a U.S. Navy aviator, at Pensacola, Florida, while visiting her cousin Corinne Mustin.
Did Earl Spencer have to leave due to World War I?
After the United States entered the First World War in 1917, Earl Spencer was posted to San Diego.
Where did Earl Spencer and Wallis Simpson live during the First World War?
Earl Spencer was posted to San Diego; they remained there until 1921.

Question: Was their marriage happy?
Self-contained rewrite: Was Wallis Simpson and Earl Spencer's marriage happy?