Michael Stirling, 32, who is the brother-in-law of the victim’s former fiance John Peake, was jailed at Stafford Crown Court on Monday, as the victim’s family watched from the public gallery.
He must serve a minimum of 17 years and 52 days.
Stirling flew into an “intense rage”, suffocating and strangling 28-year-old Eastwood before “panicking” and burying her body at a disused quarry in July of this year.
She was discovered dead in a rural area near Caverswall, Staffordshire, on 4 August, wrapped in a duvet and with tape around her eyes and face.
During sentencing on Monday afternoon, Justice Sue Carr said: “In the agonising hours and days following her death you lied and lied, over and over again, in an attempt to cover up what you had done.”
After killing Eastwood, Stirling used her phone to text her sister, Gemma, in an attempt to cover up his crime.
Justice Carr said: “You took your actions to a new level, with breathtaking cruelty. It is difficult to imagine the further appalling distress and confusion this caused to Samantha’s family and friends.”
Stirling also pretended to help in searches for her after the alarm was raised.
After admitting to the murder in October, Stirling’s barrister Charles Miskin QC, said: “This was not a pre-meditated act. The context of the killing was a background of growing tension arising from a long-standing, but not particularly intense affair.”
Eastwood was last seen leaving work at Royal Stoke Hospital at 7.45am on Friday 27 July, still in her uniform. Her colleagues raised the alarm when she failed to turn up for her night shift later that evening.
Her car was found parked in the driveway of her home in Greenside Avenue, Baddeley Green, Staffordshire, with the keys still inside.
In the days after she disappeared, the national headlines were dominated with “missing midwife” appeals for information.
Her sister made a tearful appeal for help in tracing her the 28-year-old, saying: “We miss you very much, we need you home where you belong.” Gemma Eastwood said her missing sibling was “a happy, bubbly and smiley woman” and her “best friend and partner in crime.”
“Without her, half of me has gone,” she said. “She is caring, harmless and gentle. Samantha is selfless and would do anything for anyone before herself.”
Eastwood had been in a relationship with John Peake, 34, and was engaged to be married in July. But their relationship ended in January and the wedding was called off.
It later emerged Eastwood had been having an affair with Stirling, Peake’s brother-in-law.
During the trial, Miskin said on the afternoon of the killing “there was an argument in that context and that led to [Stirling] being very angry.
“After a struggle and while she was on the floor, he put his hands over her throat, her mouth and nose, and as a result of that she died.”
“During his intense rage, he originally intended to cause her really serious bodily harm, but matters escalated and he carried out the intention to kill her.”
Her disappearance sparked a massive police operation and outpouring of public support. Eastwood’s family said in a statement after her body was discovered: “We would like to say thank you to all the people who followed Samantha’s story and tried their best to help.”