A teenage thug carried out a vicious bottle attack after finding another man naked in bed with his girlfriend.
Jordan Mullen, 19, flew into a rage when he discovered Scott McDonald and Susan McNeill between the sheets.
Mr McDonald was left scarred for life and also suffered a punctured lung after Mullen brutally attacked him with a Buckfast bottle.
Yesterday, at the High Court in Glasgow, Mullen was ordered to spend four years behind bars after admitting the assault.
Lord Bracadale labelled the incident as “serious” and also ordered Mullen be supervised for a further two years once he has been released.
The court heard how Mullen and Miss McNeill had an argument before the attack took place on August 25 last year.
He reckoned she was cheating on him after he discovered a text message that made him suspicious.
Mullen was in his flat in Camphill Road, Paisley, later that evening, along with his girlfriend and Mr McDonald.
He eventually left them alone but returned later to find the pair together in bed.
Prosecutor Shanti Maguire told the court how Mullen began lashing out at Mr McDonald as Miss McNeill tried to break them up.
Miss Maguire said: “Mr McDonald managed to break free and ran into the kitchen.
“The accused followed, carrying a Buckfast bottle, and struck Mr McDonald on the head with it, causing it to smash.
“He then began to stab at the head and face of Mr McDonald, who tried to protect himself with his arms.”
Mullen fled the scene and his victim was later taken to hospital.
The court heard that Mr McDonald had to undergo surgery on a head wound and also suffered a punctured lung.
Medics believed he could have died had he not been treated in time.
Mullen, who has previous convictions for assault and carrying an offensive weapon, later told police he had been acting in self-defence.
But, yesterday, Mullen’s lawyer told the court his client now accepts he was to blame.
Bob Mitchell, defending, added: “The victim and Susan McNeill ended up in bed naked together.
“They did not have intercourse but Mullen concluded something had happened.
“The truth of the matter is that Mullen was not mature enough to deal with the situation and he responded in a violent way, which he regrets.”