Deborah Katrina Winzar was jailed for life in July 2000 after Birmingham Crown Court jurors convicted her of murdering Dominic McCarthy - who managed the Kingfisher Care Centre for the mentally and physically disabled.
Winzar, then a senior ward sister at Kettering General Hospital, in Northamptonshire, was accused of killing her husband with an overdose of insulin - causing hypoglycaemia and unconsciousness. Mr McCarthy was rushed to hospital but never woke up, dying on February 9 1997.
He had rebuilt his life after a motorbike crash left him paralysed at 22. Mr McCarthy (34), and Winzar, even had a child together.
Prosecutors said Winzar's work gave her easy access to insulin, but the 53-year-old, formerly of Stonely, Cambridgeshire, has steadfastly denied guilt ever since, insisting that she and her husband were in a happy marriage and that he died of natural causes.
She appealed against her conviction without success in December 2002, but now her case has been referred back to the Court of Appeal by the Criminal Cases Review Commission, the watchdog that looks into suspected miscarriages of justice.
Winzar has now been released from prison, but will always have her conviction and life sentence hanging over her. Her appeal is set to be heard by three of the country's most senior judges in November.
Her legal team - led by top barrister, Clare Montgomery QC - will present expert evidence that Mr McCarthy may well have died from sepsis - a form of blood poisoning that can rapidly kill disabled people.
The case was in court this week as Lord Justice Irwin gave directions for the full hearing of Winzar's appeal.