Judge Andrew Menary KC said Ormandy was “a deeply unpleasant and very dangerous man” and that there was “no guarantee that you will be released at any particular time”.
“You had been in a relationship for about four months,” he said.
“Although there must have been good times, it was a relationship that was becoming increasingly turbulent and marked by frequent arguments.
“I’m sure Rebekah never armed herself with a knife at any time and never posed any threat to you. She simply told you to get out. That was enough to set you off on your murderous attack.”
Det Supt Ben Myers, from Merseyside Police, praised the victim’s family.
“Rebekah’s family have shown dignity and courage throughout the trial, which must have been incredibly difficult as Ormandy chose to deny the offence despite the overwhelming evidence against him,” he said.
“To claim his vicious attack was in self-defence and then trying to paint himself as a victim is utterly appalling.
“Ormandy will now rightly spend a significant amount of time behind bars and our communities are safer with him removed from the streets.”