Matthew Grady left Siobhan Stevenson scarred for life after he sliced her face open during an row.
The 31-year-old stormed into his ex’s home after shouting: ‘I will go to jail for you. I am coming through your door. I will slit your throat.’
Siobhan, 23, frantically wrapped a towel around the wound following the attack.
The 12cm wound on her face needed 44 stitches.
Grady forced Siobhan to relive her ordeal at the High Court in Glasgow after insisting he had not tried to kill her in January this year.
But, a jury found him guilty following a two-day trial and he smiled as he was led handcuffed to the cells.
Yesterday, Grady was jailed for 10 years with two years supervision after he is released.
After reading the background reports, judge Lady Stacey said: ‘The social worker has come to the conclusion, hardly surprisingly, that you are a danger to the public because of your conduct.
‘I am very conscious you went to this young woman’s house with two knives and that the injuries you inflicted on her are serious.
‘It is essential you serve a long period of imprisonment because of what you have done.’
In court, it emerged that Grady already had a criminal past – but the details were not revealed.
Siobhan got rid of Grady weeks before the attack because she believed he had been unfaithful.
On the day of the incident, he called her to try and talk things over – but went on to brand her a ‘stupid daft cow’.
She said: ‘I told him to leave. I wanted to sort my head out as I found out he had been cheating with my ex-friend.
‘He later called in a rage saying: “I am going to slash you”.’
Siobhan was in her bathroom soon after when her raging ex barged in to the flat.
She added: ‘I saw him in the mirror first. I turned around and he was running towards me with two knives in the air.’
After initially being struck on the arm, she ‘curled up in a ball’ to protect herself before crawling tot he bedroom to ‘escape for her life’, but Grady caught up, leaned over her and slashed her.
Grady was arrested by police after the attack, but lashed out at officers calling them ‘ratbags’ and ‘fucking scum’.
He eventually had to be pinned to the ground and his legs strapped together.
Grady also tried to bite a constable on the leg four times.
Before the trial, he had offered to plead guilty to assaulting Siobhan, but denied attempted murder.