The 61-year-old Mott has now been charged with assisting her to commit suicide and will appear in the Auckland District Court this month for a plea inquiry hearing.
The charge carries a maximum penalty of 14 years in prison.
English-born Mott, a master boatbuilder who has worked on superyachts around the world, told the Herald he would tell his wife's story one day but could not speak publicly yet as the matter was before the courts.
His lawyer, Ron Mansfield, said: "This shouldn't be a story of an alleged crime, rather one of genuine love and grief.
"It is truly unfortunate that in our modern society we force people to be isolated in these circumstances and then expose their loving and grieving family to the indignity of being dragged before our criminal courts in this way.
"He has been honest to the police with what he has and has not done. The question is, is that a crime in this case? No matter the answer to this question, one can only hope that cases like this may cause our society to review what we think is right and what we think is wrong."
The couple had been together since the early 1980s and each had children from previous relationships, as well as a son of their own who is now in his 20s. They met in Australia and lived in Samoa for a time, before returning to New Zealand to raise their son.
Mott is considered a skilled craftsman and spends long periods overseas building superyachts for billionaires including Graeme Hart's $100 million Ulysses and the Mirabella V, the world's largest single-masted vessel.
Before multiple sclerosis was diagnosed, Mrs Mott was an A-grade student at the University of Auckland where she studied anthropology, psychology and sociology among other subjects.
However, her health woes started in August 2007 when she tripped over and broke her shoulder. The fracture took 18 months to heal, because she had undiagnosed osteoporosis. Even once she was healed, the pain continued. This was diagnosed as neuropathic pain, a condition where the body's nerves keep sending pain signals to the brain although the injury is healed.
An MRI scan finally confirmed Mrs Mott was suffering from multiple sclerosis, where the body's immune system attacks the nerves in the brain and spinal cord. The degenerative condition is irreversible and affects the ability of the brain to send signals to the body.
Mrs Mott was diagnosed with a particularly aggressive form which caused her physical abilities to deteriorate rapidly.
Drug treatment to alleviate the pain and slow the symptoms failed and had distressing side-effects.
The police allege that as her condition worsened, the married couple began to research suicide methods and assembled a kit in September last year. Mrs Mott decided to wait until her pregnant daughter gave birth and spent Christmas with the family before ending her life.
She asked her husband to leave her alone in their Paritai Drive home on December 28. He returned home several hours later to find her dead. Their family are understood to support the decision to end her suffering. Mrs Mott also left a video diary for friends and family to watch after her death.
The Herald has been told the couple were concerned that the suicide method would fail and leave her braindead. They were also upset that Mrs Mott had to be alone because of fears anyone in the room could face more serious criminal charges.
They believed New Zealand should allow euthanasia by a professional, as in some Scandinavian countries, because it is safer and family can be with them.
The charge of assisting suicide laid against Mott comes a few months after Sean Davison was sentenced to five months' home detention after he admitted that he "counselled and procured" the suicide of his terminally ill mother in Dunedin.
He was originally charged with attempted murder and was to stand trial until he pleaded guilty to the amended charge.
The 50-year-old was charged in 2010, 15 months after publishing a book detailing the last few months of his 85-year-old mother's life and how, at her request, he gave her crushed morphine tablets in a glass of water.
"I would never do it again, but I don't regret what I did," Davison said after his sentencing.
The voluntary euthanasia debate hit headlines in New Zealand when nurse Lesley Martin was sentenced to 15 months' jail in 2004 after being found guilty of the attempted murder of her mother, who had terminal cancer.
She founded Exit New Zealand, which campaigns for law changes to allow voluntary euthanasia.
