A judge told Sheena Watters that her unprovoked attack on Alistair Green was "extraordinarily violent".
She pounced on the 54-year-old at his Ayrshire home - then later lied to police that she had found him badly hurt.
Watters, 46, returned to the High Court in Glasgow after earlier admitting assaulting Mr Green to the danger of his life.
Lord Turnbull jailed her for 49 months, reducing the sentence from five and a half years.
The judge told Watters: "You perpetrated an offence of the most extraordinarily violent nature. The consequences for Mr Green were severe indeed. It is perhaps surprising that he survived the attack."