A former PC who planted a GPS tracker in the boot of his wife's car and checked her phone messages has admitted controlling or coercive behaviour.
Mark Howell-Walmsley, 58, of Capel Curig in Conwy, had previously denied the charge but changed his plea after Sharon McCaig started giving evidence.
His "possessive and controlling" behaviour kept Ms McCaig awake at night, she told Mold Crown Court.
Howell-Walmsley was bailed ahead of sentencing on 21 May.
The ex-community police officer admitted controlling or coercive behaviour between November 2019 and March last year.
Inspected her phone
The court heard Howell-Walmsley had required Ms McCaig to make her mobile phone available for inspection and insisted on accompanying his wife on the school run.
He had also demanded photographic proof of her visiting her elderly mother in Cheshire, and placed the tracker in her car to follow her movements, prosecutors said.
Ms McCaig, who ran a small shop as an artist in Llanberis, said they had been in a relationship since 2015 and married in May 2017.
But there had been a "series of issues" with his "possessive and controlling" behaviour and accusations, which kept her awake at night.
The court heard Howell-Walmsley had insisted Ms McCaig remove her mobile security code, which allowed him to check her messages.
"He wanted to know everything I did on my phone. I had nothing to hide," she told the jury.
Eventually Ms McCaig told her husband she wanted a divorce, but in March last year he turned up at a Tesco store in Bangor and the tracker was found by police.
Granting Howell-Walmsley bail after he pleaded guilty, Judge David Hale indicated the offence was "within the band of a community sentence".