Mary Kean, 47, told a jury her husband William, known as Billy, had been admitted to hospital following an apparent suicide bid on March 19.
On March 29 she visited her husband, who denies murdering Mrs Methven at her cottage in Forteviot, Perthshire, on February 20 this year, at Murray Royal Hospital in Perth and he was allowed to go out to a nursery in Scone, Perthshire, with her.
Defence QC Brian McConnachie asked: "Was it while you were there that Billy was detained by the police?" She replied: "Yes."
Mrs Kean cried as she replied to Mr McConnachie's questions.
She was asked: "Had you anticipated the police were going to arrest him?" She replied: "No."
Mr McConnachie then asked: "Did it come as a shock to you?" Mrs Kean said: "Yes, very much."
She was asked if she had ever known her husband to be in any trouble with the police or the authorities and said that eight years ago he was caught using his mobile phone while driving.
Mrs Kean told the jury that from February 20, the day Mrs Methven died, until March 19 when her husband was hospitalised after an apparent suicide bid, she had not noticed anything unusual about him.
Mr McConnachie asked: "During all that time, there was nothing in Billy's behaviour which led you to think there was something untoward in his behaviour, that he was anxious or guilty about having committed a murder?" She replied: "No."
She was then asked if there was anything to suggest he was anxious or guilty about having discovered a murder, and she said: "No."
Mrs Kean described her husband of 15 years as quiet, reserved and a private person.
While re-examining Mrs Kean, prosecutor Alex Prentice said: "Do you know that it is a matter of agreement in this case that Mr Kean touched the lower right arm of Jenny Methven on the day she died? Did he ever tell you that?" She replied: "No."
Earlier she was shown a pair of dark blue cord trousers and said that one day – she could not remember exactly when – her husband came home and said he had spilled something on them at work.
Mrs Kean, a mother-of-one, said she told him they were ruined and told him to put them in the recycling bin in the garage. The jury has heard the cords were found by police in the eaves of Kean's garage.
Detective Constable Rosemary Reid, 38, who was the first CID officer on the scene, told the court it was odd that despite the amount of blood and Mrs Methven's injuries, her glasses were not damaged or blood-spattered. She said of the glasses: "They were perfect."
There was no blood on the spectacles despite the fact there was blood running down Mrs Methven's face and her left eye was black. DC Reid said it was possible the glasses had been put on Mrs Methven's face after she had been attacked.
The CID officer said she spoke to Mrs Methven's son David, who found her body in the kitchen of the cottage they shared when he came home from work after 5pm. She said she found him devoid of emotion and showing no signs of grief.
Kean denies murdering Mrs Methven and has lodged a special defence blaming David Methven.
It is also alleged he attempted to defeat the ends of justice between February 20 and March 28, 2012, by pouring bleach on to a pair of bloodstained trousers, and then hiding them in the eaves of a garage in Blairgowrie, Perthshire.
Kean is also charged with attempting to pervert the course of justice between March 13 and 19 by failing to turn up at Perth Police headquarters to have his fingerprints taken and repeatedly cutting his fingertips and palms to prevent police taking usable samples.
Kean denies all the charges against him. The trial before Lord Glennie continues.
trial: Mary Kean, wife of murder accused Billy Kean, leaves court