Christopher Steele's colourful life as an MI6 spy took him from Russia to Afghanistan via Paris, before his wife died at the tragically young age of 43.
Mr Steele, 52, founded his private investigations company, Orbis Business Intelligence, in March 2009.
But just six months later, his wife Laura died of cirrhosis of the liver, leaving him heartbroken and to bring up their three children alone.
Friends and family shared fond recollections of the couple's life of intrigue during orations at Mrs Steele's funeral.
They had met on a double-date in 1988 with one of Mrs Steele's male colleagues, who recalled that her diary date for the day read: "Lunch at 12.30 with Sue, Neil and Chris Whatsit."
Mr Steele was a "fast mover" and by the end of the year he had proposed. The couple were married in July 1990.
Mr Steele, already working for MI6 after being recruited from Cambridge University, was posted to Moscow months later, where the couple faced "constant harassment" from the KGB, Neil recalled, which even included the theft of Mrs Steele's favourite pair of shoes from their flat.
Officially listed as Second Secretary (Chancery) in the British Embassy, Mr Steele worked closely with Sir Tim Barrow, the new ambassador to the EU, and Alex Younger, now head of MI6.
The couple returned to London in 1993 and had two sons, Matthew and Henry, before Mr Steele took up a posting to Paris in 1998, where their daughter Georgina was later born.
At first, they lived in a flat owned by the pop singer Annie Lennox on Rue Bonaparte before moving outside the capital. The first signs of Mrs Steele's illness emerged and they returned to the UK in 2002.
Mr Steele's expertise on Russia remained valued, and he was selected as case officer for the FSB defector Alexander Litvinenko, whose state-sponsored assassination in 2006 affected him deeply.
When he left the Secret Intelligence Service to set up his firm, it quickly prospered. Accounts show profits of more than £1m (€1.2m) in the past two years, thanks partly to a commission from the Football Association to investigate corruption at football's world governing body FIFA.
The FBI is reported to have consulted him before it arranged the arrest of several officials, leading to the resignation of the then president Sepp Blatter.
Since his wife's death Mr Steele has married again and had another child.
The family live in a £1.3m (€1.5m) home in Surrey dotted with CCTV cameras.