Kirsti Windsor is accused of killing David Langdon when he refused to move out of the remote cottage they shared.
The horse trainer allegedly tried to incinerate his corpse on a number of occasions but failed.
She even tried to cover up the killing by telling police Langdon had “committed suicide by jumping on the
bonfire”, it was said.
Windsor has pleaded not guilty to killing Langdon between August 9 and 12, 2008 and perverting the course of justice.
Her friend Katie Brown, 31, is accused of perverting the course of justice by helping Windsor burn Mr Langdon’s body.
On January 13, on the first day of a seven week trial, a jury was told how Windsor had ended the couple’s longstanding relationship after a series of violent rows.
Worcester Crown Court in England heard how Windsor ordered Langdon to leave Wood Cottage in Wormelow, Herefordshire, after he tried to strangle her.
But he refused and when she returned from a trip to the Lake District on August 9 she discovered he was still there. Three days later his charred remains were found.
Between August 10 and 13, villagers reported seeing plumes of smoke coming from the couple’s back garden and rancid fumes which smelt like “burning bones”.
Christopher Millington QC, prosecuting, told the court: “Miss Windsor returned home expecting him to be long gone but clearly she was mistaken.
“Only two people know what happened to Mr Langdon at the cottage, one of them is dead and the other is Miss Windsor.
“Unhappily for Miss Windsor, it proved more difficult to incinerate a human body outdoors than she realised.”
A post mortem failed to reveal an exact cause of death.
Mr Millington added: “This was no ordinary bonfire. It contained two tyres, a body, two wooden doors and petrol paraffin to help it light.”
The trial continues.