Eliska Novotna was found guilty of the culpable homicide of Arunus Ramanauskas at the property they shared in Easter Happrew Farm, Peebles on Saturday, October 8, 2011.
Officers found the 39-year-old within his home having sustained a number of puncture wounds to his chest.
Despite the efforts of ambulance staff, Mr Ramanauskas died at the scene as a result of his injuries and Lothian and Borders Police launched a major enquiry into his death.
Detective Chief Inspector Jim Robertson who led the investigation said: "The full circumstances as this incident in which Arunus Ramanauskas suffered ultimately fatal injuries may never be known.
"However, Lothian and Borders Police conducted a robust investigation to prove that Eliska Novotna was involved in his death and today's verdict reflects that.
"My deepest sympathies remain with Mr Ramanauskas's family at this time and I hope they can now begin to move on with their lives."