Brendon Constant, 87, was accused of smothering his 86-year-old wife Jean with a plastic bag at Poppyfields care home in Eynesbury, near St Neots.
He died in hospital after suffering "catastrophic" head injuries in a fall at home, Cambridge Crown Court heard.
Mr Constant, of Richmond Road, Wisbech, did not enter a plea to the murder charge before his death.
Cambridge Crown Court heard he had attempted to kill himself at the same time as his wife was killed last August but survived and faced court proceedings.
His barrister, Sally Hobson, said he suffered a fall at home on April 27 after celebrating his grandson's birthday and that there was "no suggestion he took his own life".
She said: "When he retired to bed, he spoke briefly to his great-granddaughter, then went upstairs and fell and suffered catastrophic head injuries."
Mr Constant was taken to Addenbrooke's Hospital in Cambridge and his family agreed to switch off his life support machine the following day.
"He had hoped to end his life together with his wife in August last year in circumstances they hoped would cause the least distress and discomfort," Mrs Hobson said.
Judge David Farrell voiced concerns over the fact Mr Constant had been granted bail and fell at home.
He said: "Everyone thought he was in a safe environment so I'm concerned all proper care was given to him."
A post-mortem examination concluded that Mrs Constant died of asphyxia in association with heart disease.
Her body was discovered by police who were called to Poppyfields care home in Chapman Way, Eynesbury, near St Neots, on August 22.
A man charged with murdering his wife at a care home has died before his court case could be heard.