A court Edward Leo McCreesh struck his victim so hard that part of his scalp was removed, exposing his skull.
Welder McCreesh, 45, stole a protective suit from work and sprayed it black and wore a ski mask to carry out the attack.
Leeds Crown Court heard McCreesh turned violent after finding texts on his girlfriend’s phone which revealed she had been having a sexual affair with the 61-year-old victim.
McCreesh had previously challenged them after becoming suspicious when he read Facebook messages which they had exchanged.
Jonathan Sharp, prosecuting, said McCreesh and his partner knew the victim from socialising in the Brown Hare pub, Harehills. Leeds.
He said: “(The victim) had an affair with the defendant’s girlfriend and this was carried out as revenge.”
The prosecutor said McCreesh remained “outwardly calm” after finding the texts on his partner’s phone on April 28 this year.
McCreesh went to the pub two days later and behaved normally towards to victim.
McCreesh left the pub at 1am the next morning then walked two miles to the victim’s home in Halton and waited for him outside.
The victim was attacked after he returned home then went outside to put money in his electricity meter.
McCreesh is thought to have used a piece of wood to hit him over the head from behind. McCreesh continued to hit him around 20 times.
His mask slipped during the attack and the victim recognised McCreesh.
McCreesh went back to his girlfriend’s house after the attack and dumped his disguise in the garden.
The victim was taken to hospital by ambulance. He suffered multiple wounds to his head, face and body but his injuries were not life threatening.
McCreesh, of St Wilfrids Avenue, Gipton, was jailed for eight years after pleading guilty to wounding with intent.
Mark McKone, mitigating, said: “He accepts that the law does not allow him to react as he did, but this is the sort of situation that can cause ordinary decent people to lose their temper and to lose their good sense.
“This is the first custodial sentence for Mr McCreesh. He will find it difficult at his age to get his life back together when he is released.”
The Recorder of Leeds, Judge Peter Collier, QC, said: “It was miraculous that there were no other fractures to his head or body or any other injuries.”