Pattinson is now rumoured to be dating Elvis Presley's actress granddaughter Riley Keough.
"Kristen feels betrayed and hurt that Rob is moving on so quickly after their intense four year romance," femalefirst.co.uk quoted a source as saying.
Pattinson who was also linked to singer Katy Perry after being spotted with her at a Bjork gig in May, is said to have first met Keough through Stewart.
"Riley and Rob are glued to each other's side. Rob's awestruck that he's dating someone related to Elvis as he's a massive fan of rock 'n' roll," the source added.
If their relationship blossoms, the new couple could even potentially star in a joint advertising campaign. Pattinson is the face of aftershave Dior Homme, while Keough used to represent perfume Dior Cherie and still has ties with the company.