Timothy Walkey, aged 48, was due to face trial accused of the attempted murder of 46-year-old Jennifer Walkey in Saltash.
But he pleaded guilty to the lesser charge of causing her grievous bodily harm with intent on August 4 last year.
Prosecutors accepted his plea and the trial on the attempted murder charge was aborted.
Sitting at Truro Crown Court, Judge Simon Carr jailed him for nine years and six months.
Walkey had admitted possession of a lock knife without good reason or lawful authority in a public place, Warfelton Crescent in Saltash, on the same day. He received no separate penalty.
Police said they were called to a domestic incident on the housing estate late on that Thursday morning.
Mrs Walkey was treated for serious injuries at the intensive care unit of Derriford Hospital.
Walkey, who gave his address as Warfelton Crescent, was arrested soon after the incident and remanded in custody by Bodmin magistrates the next day.
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