Warrant Officer Gary O'Donnell, from Edinburgh, was attempting to tackle a roadside bomb near Musa Qala, Helmand, when it exploded, killing him just weeks after the birth of his son.
A few weeks earlier the 40-year-old, became the first servicemen in 30 years to win the George Medal twice for saving countless lives in Iraq and Afghanistan. The second award, an incredibly rare feat, came after he spent 24 hours defusing 11 Taliban bombs, one of which was triggered as he approached it but it failed to go off.
He left behind his wife, Toni, 44, and four children - Cayleigh, Dylan, Aidan and Ben, who was just nine weeks old when his father was killed in September 2008.
Now Mrs O'Donnell has made the difficult decision to sell her husband's unique and outstanding medal group that includes the George Medal and Bar. They are expected to sell for £60,000.
Pierce Noonan, of London auctioneers Dix Noonan Webb, said: "Her reasons for selling the medals are simply that she has a young family to provide for.
"It has been an extremely difficult decision for her to make but because the value of them is between £50,000 to £60,000 the money is more useful to her and her family now. The medals are unique as they are the only George Medal and Bar to be awarded to a servicemen in the modern era.
"Gary O'Donnell was extremely brave but what you have to bear in mind with bomb disposal experts is that it is pre-meditated bravery, not on the spur of the moment. It must be a long and lonely walk for these people to make knowing that it could be the last thing they do."
WO O'Donnell, from Edinburgh, was part of the Royal Logistics Corps elite bomb disposal unit and served in Sierra Leone before going to Iraq in 2006.
He won his first George Medal - the second highest award for gallantry not in the face of the enemy - for his persistent courage in defusing numerous bombs.
One of the heroic acts was disabling a live rocket that was set to a timing device and aimed at the British base at Basra, which housed 4000 personnel. He chose to place himself directly in the firing line of the rocket to defuse it in the shortest time possible.
WO O'Donnell had defused about 50 improvised explosive devices (IED) during two tours of Afghanistan, before he was killed in September 2008.
While making safe one of the bombs, he came within milliseconds of being killed when he jammed his fingers into a crude clothes peg trigger just as it slammed shut.
The citation for his second George Medal, which was awarded posthumously, stated that WO O'Donnell was flown to a convoy after its bomb disposal operator collapsed due to exhaustion.
It read: "Over the next 24 hours, under increasing pressure and immense fatigue, he rendered safe a total of 11 IEDs.
"His calm and pragmatic approach to the task had belied the immense personal danger he repeatedly placed himself in."
He was killed just days away from the end of his second tour in Afghanistan.
The medal set includes the George Medal and Bar, General Service Medal Northern Ireland, Operational Service Medal Sierra Leone, Iraq Medal 2003, Operational Service Medal Afghanistan, NATO Medal, ISAF Medal, Jubilee 2002 Medal, Accumulated Campaign Service Medal and Regular Army Medal.
The auction takes place on September 20 in London.