An 84-year-old man was in a Cologne court on Monday on charges of manslaughter after killing his wife of 58 years in 2017. The defendant told the court that he wanted to "spare her" the indignities of infirmity as she slipped further into dementia, German news agency DPA reported.

"She didn't want to live anymore, she said that almost daily," he said, adding that she routinely threatened to kill herself. Prosecutors have argued that there is no second witness to confirm that the woman, 80, wanted to commit suicide.

In May 2017, in their home in the western German town of Bergisch Gladbach the man gave his wife a fatal dose of sleeping tablets, according to Die Welt daily. He tried to kill himself as well, but survived. He then messaged his children to tell them of their mother's death. He told the court that had not informed them of his plan, due to his own doubts over whether to carry it out.

In his suicide note that was read to court, he had written that his own strength was also at an end. The two had always planned to die together, should one of them develop a disease like Alzheimer's, he said.

The case is expected to continue into February.

In 2017, a court in the eastern city of Leipzig ruled that patients should be given access to life-ending drugs "in extreme circumstances," about two years after Germany banned "commercial" euthanasia centers. However, a set of nationwide guidelines has not been established.