The couple travelled to Te Anau to celebrate a belated honeymoon after marrying in April 2019.
Both the Crown and the defence accepted that the victim was killed in the hotel room by Fallowfield, but they disputed the intent.
The Crown's case was Fallowfield strangled her as he wanted his wife to be quiet when she threatened him with a rape allegation, while defence said he "snapped" but did not have the intention to do so.
Reedy's family was present at court on Friday and their distress at the outcome was visible.
Before court, White Ribbon ambassador and family supporter Jamie Addison performed a whakawātea, which he explained was a ceremony to bring closure to the family.
Reading her victim impact statement in court, sister Roxanne Reedy said the loss had left a huge hole in their lives.
"[We are] wondering why or what did she do to deserve this. To die at the hands of another person, someone she calls husband."
The way Fallowfield acted and the comments he made to the police that he had "treated her as queen" or that he had snapped did not made sense, Roxanne Reedy told the court.
"Why was she yelling rape, when half and hour or so before there was a photo posted on Facebook of you two happily celebrating your wedding anniversary? It doesn't make sense.
"If she really was your queen, why did that happen? And why didn't you call for medical help?"
Another six family members and friends read emotional victim impact statements and described Reedy as kind, with a gold heart and cherished by the family.
Personal and treasured belongings of Reedy's, including a childhood toy and a newspaper, were placed in a court box during the sentencing.
Justice Doogue acknowledged the pain and loss of the family and read a message to them in te reo. She also spoke about the strength and love the family had for Reedy.
"That connection will always endure and so will your responsibility for their pain," she told Fallowfield.
Justice Doogue accepted that the court process and sentencing would never restore or heal what had been taken from the family.
However, she said she had to impose a sentence considering other manslaughter cases in the court system, as well as Fallowfield's mitigations factors.
Among these was the hardship he faced throughout his life, which included parental negligence and sexual abuse in childhood.
His early admission of the killing, his remorse and willingness to engage in the restorative justice with Reedy's family, as well as undertaking treatment while in jail, were also highlighted.
Justice Doogue set a starting point of seven years and nine months of imprisonment, but allowed a 44 per cent discount, giving a final sentence of four years and three months.
