Bill Starr (76) claims he has been told that his wife, Maureen, who suffers from Alzheimer's disease, is now dying.
Hucknall-born Maureen (63) has been a resident of the Lowmoor Home at Kirkby-in-Ashfield for 18 months.
But she no longer recognises her husband and Bill told the Dispatch that he called at the home last week "with the sole intention of releasing my wife's spirit".
He even took a change of clothes because he was prepared for police to arrive and arrest him.
He declined to say how he planned to carry out the mercy killing, which would have been illegal.
Because staff became aware of what Bill proposed to do, he has now been told he can no longer visit Maureen without supervision.
A campaigner for voluntary euthanasia, Bill says he will not be going to see Maureen any more in any case because he cannot bear to watch her condition deteriorate.
He visited the home this week to say his final goodbyes and he is now appealing for friends in Spiritualist churches to pray for Maureen's "early transition from this life".
In the meantime he has written to staff at the home to ask them to make sure Maureen receives a lot of tender loving care.
He says: "It was a heartbreaking decision not to see Maureen any more but I felt it was something I must do.
"I do not really care what happens to me now but I will carry on just for Maureen's sake."
Born in Bulwell, Bill used to live on Curtis Street in Hucknall. He is now a resident of Aspley.
He formerly worked at Newstead Colliery and was a leading fighter for miners to receive compensation for the disabling condition, vibration white finger.
Up to now, Bill has visited Maureen every single day while she has been at Lowmoor.
He spent 11 hours a day with her to ensure she received one-to-one care and he became regarded almost as an unofficial member of the staff.
But his attitude changed when a nurse at Lowmoor allegedly informed him that his wife's brain cells were dying and she would be lucky if she was still alive this time next year.
"I was told it would be downhill all the way for Maureen from now on," he said.
Bill has unsuccessfully pressed for a change in the law to allow voluntary mercy-killing.
He says he is "very disappointed" with a reply sent on behalf of the Prime Minister because it shows an "infantile mentality".
"Alzheimer's, dementia and assisted suicide do not require matters of consciences, Parliamentary debates or rules and regulations," he says.
"There is a lot of buck-passing by people who should know better and they are letting down those who deserve better."
Alzheimer's is a terrible progressive disease that can lead to sufferers no longer recognising loved ones.
"But I was told that Maureen's spirit is as strong as a stallion's," said Bill.
A spokesman for the privately-owned Lowmoor Home stressed that it was Bill's own decision to stop visiting Maureen.
"He will still be welcome if he changes his mind but he must be escorted by a staff member," said the spokesman.
"There is no way we can condone or allow euthanasia, which is illegal, and we have a duty of care to protect Maureen.
"We invited Bill to a meeting of doctors and the social services to discuss his concerns but he refused to come."
The spokesman said he was unaware of anyone at the home telling Bill that Maureen was dying.
"He knows there is no cure for her condition, which will inevitably deteriorate," said the spokesman.
"But we cannot say for sure how much longer she has to live."