Kristen Stewart was reportedly texting her fling Rupert Sanders recenlty and that is why Robert Pattinson ended their relationship over the weekend.

Pattinson discovered that Stewart was still in contact with her Snow White and the Huntsman director, The Sun reported Tuesday.

Stewart admitted to an on set romance with Sanders in 2012 after pictures surfaced online of the two being affectionate. The newspaper alleged that while Stewart was in the shower, Pattinson discovered she was still in contact with Sanders on the morning of his 27th birthday (May 13) when he saw an incoming text on Stewart's phone from Sanders. The paper added that an upset Pattinson got up and left over what he thought was another betrayal by Stewart.

"Despite Kristen's pleas, he told her not to come to his birthday party at a friend's that night. He's extremely angry and upset," the source said. "No matter how many times she calls or texts, friends say he's had enough."

The source close to the couple also said that Pattinson was furious that Stewart would have any contact with the director after the hurt he caused. Furthermore, Pattinson was described as not caring if the contact between the two was innocent.

"It does look like this time it's over for good. He simply can't trust her," the source said.

Sources confirmed that the Twilight stars separated after more than three years of dating on May 18.  It was a split that many in their inner circle saw coming, as the two had been spending more time apart.

Tensions between the couple mounted when Pattinson reportedly blew off a 27th birthday party that Stewart arranged for him. At the last minute, he changed his mind about attending the gathering and decided he did not want a big deal to be made of his birthday. He decided to celebrate with his friends instead and Stewart was not invited to those celebrations.

"He had friends over at his house, but Kristen was not part of the celebration," the source said. "For the past few days, they have not spent any time together."

Sources believed that Pattinson never fully forgave Stewart after she cheated. Stewart allegedly felt that Pattinson no longer treated her the way that he used to.

"He's not as into it as he was before the cheating - not giving her special treatment like he used to. She feels unloved and that's why they fought," a source said