Alison Skingsly drove away from the car park of the Olde Bridge Inn at Crowland with Kevin Nix, 46, holding on to the bonnet in an attempt to prevent her drink driving.
Skingsly, who had spent the afternoon at the pub drinking with Mr Nix, continued along a country road and over a bridge before stopping suddenly.
Mr Nix was thrown from the car and struck his head on the road. He suffered traumatic brain injuries and died three days later in hospital.
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The jury at Lincoln Crown Court cleared Skingsly of murder but found her guilty of manslaughter.
Judge John Pini QC remanded her in custody to await sentence on a later date.
James Thomas, prosecuting, said “Alison Skingsly had been in a relationship with Kevin Nix since 2013.
“On Sunday 24 June 2018 they went together to the Olde Bridge Inn pub near Crowland. It was a location they had frequented on a number of occasions previously.
“That afternoon they travelled there in their Peugeot 307.
“Following an afternoon drinking at the pub an argument developed.”
He said Skingsly accused Mr Nix with flirting with another woman and then stormed off into the pub’s beer garden.
Minutes later she drove away with Mr Nix clinging to the bonnet only for him to then fall off.
Police arrived at the scene to find Mr Nix unconscious and bleeding from his head. Skingsly was arrested after she failed a breath test producing a reading of 64 mgs of alcohol per 100 mls of breath putting her over the legal limit of 35 mgs.
Skingsly, in evidence, said she never intended to injure Mr Nix. She claimed she braked sharply and he was thrown off.
She said she feared she would be assaulted by Mr Nix and told the jury he hit her when they were in the beer garden.
“I was very frightened. I thought he was going to come out and hit me again. He looked really angry. I just wanted to get away from him,” she said.
Skingsly, 43, of Thames Road, Spalding, denied the murder of Mr Nix on 27 June 2018 and also denied an alternative charge of manslaughter. During her trial she appeared by video link from Peterborough Prison where she has been held in custody. The jury was told she has a serious back condition which prevented her from travelling.