Bioscientist Samantha Ho, 39, was found dead at a house in St Neots, Cambridgeshire, in September last year.
Her head and body were discovered separately and a post-mortem examination concluded she died after suffering multiple cuts to the neck.
In December, her husband, Timothy Allen, 40, of Curlew Place, St Neots, pleaded not guilty to murdering her on August 29 2015.
His trial was due to start at Cambridge Crown Court earlier this week, but during a brief hearing before Mrs Justice McGowan at the Old Bailey today, he pleaded guilty to manslaughter by diminished responsibility.
The plea to the lesser charge was accepted by the prosecution and sentencing was adjourned until March 17 at either a London crown court or in Cambridge.
The defendant entered his plea via video link from Wymondham Police Station in Norfolk.
PA
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