The body of Aaron Armstrong, 25, was discovered at his home in Blyth at 12.20pm on Tuesday.
A Northumbria Police spokesman said: “At around 12.20pm on 10 July, police received a report from the ambulance service that a 25-year-old man had been found deceased at a property on Furnace Road in Bebside, Blyth.
“There is not believed to be any third party involvement and a report will now be prepared for the coroner.”
The day before his death, Armstrong uploaded a picture to his Instagram account of himself and his late girlfriend.
Armstrong had posted a number of tributes to Gradon on his social media page, sharing images of the two together on nights out and on holiday.
In a post on Instagram uploaded shortly after his girlfriend’s death, Armstrong wrote: “To think I will never see your beautiful smile again haunts me you are the girl of my dreams we spoke of having kids and spending the rest of are lives together I’m so devastated that we will never get that chance to grow old together and raise a family.
“I love you with all my heart Sophie u will always be in my heart you are my angel and I know you will be by my side everyday (sic).”
Gradon, who starred on the second series of the popular ITV reality show, was laid to rest on Thursday in Jesmond, Newcastle-upon-Tyne.
She was found dead at her parents’ home in Medburn on June 20 at the age of 32.
The cause of her death has not been confirmed but police have stated they are not treating it as suspicious.
Her parents broke their silence on her death last week, telling ChronicleLive: “It has been one week since we lost our precious daughter and we as a family are still coming to terms with our sudden loss.
“Our hearts are broken. We wish to say our goodbyes to Sophie in private so we ask that you respect our family’s privacy during this arduous time.”