A "devoted" mum's death remains a mystery to doctors after her husband found her lifeless in bed aged just 32.
Just an hour after Stacey Frere, kissed her husband Ben goodnight, he saw her lips had turned blue and feared she was unconscious.
She had died in her sleep two weeks before Christmas but a post-mortem revealed no sign of what from, according to reports.
Ben, 36, who tried to resuscitate Stacey, said: "I knew something was wrong straight away as I couldn't hear her breathing and her lips were blue. I panicked.
"I didn't know what to do. I was pressing her chest, trying to get her breathing. But it was too late."
Emergency services were unable to bring Stacey back when they responded to Ben's call for help at their Fullers Slade home in Milton Keynes.
Ben was then tasked with breaking the news to their young children, Lottie, seven, and Tyler, nine, who were asleep in their bedrooms at the time of their mum's death.
He said: "I was in such shock I don't even remember what I said. I think I just told them mummy had gone to be with their grandma and grandpa, who died a while ago."
"It was so sudden and so unexpected. Nobody can even tell us why she died. They miss her terribly. We all do.
"She was the most caring, lovely person. She never put herself first and would always be there to help others."
As the grieving family were waiting on toxicology and tissue sample results, doctors told them Stacey could have been one of around 500 Brits to die each year from Sudden Adult Death Syndrome.
Ben was Stacey's full-time carer due to her obesity which gave her serious mobility issues.
A few days before she died, Ben explained how Stacey went to hospital with high blood sugar but a post-mortem found no problems with her heart or kidneys.
Ben added: "She was a big girl. She weighed 30 stone. She had always been quite big but she put on weight after having each of the babies and couldn't lose it.
"She had ulcers on her legs was finding it difficult to get around and manage stairs and things,' said Ben.
"Her blood sugar was still a bit high when she was discharged, but they had scanned her and tested her and said she was fine.
"She had actually spoken to the doctor the day before she died about going on a bariatric programme to lose weight and perhaps have a gastric band fitted."
Relatives hope to cover Stacey's funeral costs with a fundraising page.