WO Upton, from the 5th Regiment Royal Artillery, died in an explosion while on foot patrol in the Sangin district of Helmand province last month.
Mrs Upton, 32, said she would wear the Elizabeth Cross "with pride and treasure it always".
"It is an absolute honour to receive the very first Elizabeth Cross in Her Majesty's name and comforting to feel the support of Queen and country," she said.
"Sean and I grew up together, were childhood sweethearts and soul mates. He was a loving husband and devoted father.
"Sean was an outstanding soldier, loved his job and was part of the Army family."
The Elizabeth Cross is awarded to the next of kin of armed forces personnel killed on active service, in national recognition of their loss.
The funeral cortege of the three soldiers who were repatriated was driven through the Wiltshire town of Wootton Bassett on Tuesday afternoon.
The three men were on foot patrol when they were killed
A private service at RAF Lyneham's chapel of rest took place beforehand.
Capt Hale's aunt, Margaret Arney, thanked the "tremendous" people of Wootton Bassett and said her nephew had always been a "hero".
"He was well respected in the military and we all adored him. It is a very sad loss to everyone," said the 62-year-old.
"We can't come out now - it would make a mockery of his death."
Rifleman Wild's ex-girlfriend, Tara Lambell, 16, said he was "great guy" who "would do anything for anyone".
"It is the first time I've been here and it's really emotional to see so many people," she said.
"Many of them didn't even know the soldiers who are coming through."
Lance Bombardier Hatton, from North Yorkshire, of 40 Regiment Royal Artillery, was hit by a bomb in Helmand on Thursday.
Rifleman Wild, from County Durham, and Capt Hale, from Bournemouth, both serving with the 2nd Battalion The Rifles, were carrying their wounded comrade when the three men were hit by the second explosion.
Capt Hale died later from his injuries, while Lance Bombardier Hatton, from Haxby, and Rifleman Wild, from Easington, died at the scene.
The three men were on foot patrol providing security for a meeting ahead of the country's presidential elections when they were killed.
Soon after their deaths, the number of British military fatalities in Afghanistan surpassed 200. It now stands at 204.
Lt Col Rupert Jones, commanding officer of 4 Rifles, described Capt Hale as "a legend".
Lt Col Rob Thomson, of the Rifles Battlegroup, said Rifleman Wild was a "fearless" soldier who was adored by his men.
Lance Bombardier Hatton's parents Jill and Philip said in a statement: "He was very brave and a credit to both us and the Army. We are really proud of him."
On Monday, Defence Secretary Bob Ainsworth insisted that the UK campaign in Afghanistan remained "winnable", as MoD figures revealed the number of British military injuries in the country had more than doubled in a month.
A total of 94 UK soldiers were injured in action in Helmand in July, compared with 46 in June.
A further three soldiers killed in a blast in Afghanistan were named by the Ministry of Defence.
Fusilier Simon Annis, from Salford, Fusilier Louis Carter, from Nuneaton, Warwickshire, and Lance Corporal James Fullarton, from Coventry, were all members of the 2nd Battalion of the Royal Regiment of Fusiliers and died in an explosion near Sangin on Sunday.
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