Hans Kristian Rausing, heir to the Tetra Pak fortune, pleaded guilty on Wednesday to delaying the burial of his wife after her body lay rotting at their London mansion for two months.
The 49-year-old millionaire said in a statement read to court that he had been unable to "confront the reality" of the death of his US-born wife Eva and tried to act as if it had not happened.
Rausing pleaded guilty at Isleworth Crown Court in London to preventing the lawful and decent burial of his wife and to a separate charge of driving a vehicle while unfit through drugs.
He will be sentenced at a later date.
Rausing was originally arrested last month on suspicion of murdering his 48-year-old wife, after police found her decaying body under a pile of clothes and bin bags at their luxury home on July 9.
A post-mortem found that Eva Rausing, one of Britain's richest women, had died two months earlier and had drugs in her system, including cocaine.
"I do not have a very coherent recollection of the events leading up to and since Eva's death," Rausing said in a statement to police after his arrest, which was read out to the court.
"Safe to assure you that I have never wished her or done her any harm. I did not supply her with drugs. I have been very traumatised since her death," he said.
"I do not know what caused her death. I did not feel able to confront the reality of her death. I do not feel, with the benefit of hindsight, that following her death I acted rationally.
"I tried to carry on as if her death had not happened and batted away any inquiries about her."
He added: "I believe, in the period since Eva died, I have suffered some form of breakdown."
At the previous hearing on July 18, Rausing was ordered to reside at a psychiatric hospital. Photographs in the British press this week showed him looking dishevelled while being accompanied by a helper on a shopping trip.
The Rausings, who have four teenage children, had struggled publicly with drug addiction for many years and were known for their generous donations to addiction charities.
The couple first met at an addiction clinic and were charged in 2008 after Eva tried to take crack cocaine and heroin into a function at the US embassy in London.
The Rausing family is worth £4.3 billion pounds ($6.7 billion, 5.5 billion euros), according to this year's Sunday Times Rich List.
Rausing's father Hans, 86, developed the Tetra Pak business founded by his own father into a multi-billion dollar operation that revolutionised the packaging of food and drink, but sold his stake in 1995.
The defendant's father moved to Britain with his wife Marit in 1980 in order to avoid Sweden's high tax rates, and they live on a vast estate in East Sussex, southern England.
In a statement after an earlier hearing, the family said: "Her death, and the details of subsequent events, are a reminder of the distorted reality of drug addiction.
"They desperately hope that their dear son, Hans, may find the strength to begin the long and hard journey of detoxification and rehabilitation."© ANP/AFP