Robert Pattinson and Kristen Stewart's families were stunned by her admission she had cheated on him.

The actress made a public apology to her boyfriend last week after admitting to an affair with her 'Snow White and the Huntsman' director Rupert Sanders and the news came as a shock to the couple's loved ones as they were expecting them to marry.

A source said: "Rob and Kristen have been closer than ever recently, and until this week the family was expecting them to get engaged."

Despite Kristen's public apology and declaration of love for her 'Twilight Saga' co-star, the British actor - who has moved out of their Los Angeles mansion - is said to have been "indifferent" to the statement and is struggling to get to grips with the situation.

The source added to Grazia magazine: "Rob was indifferent to her statement. Kristen wrote it and she's desperately trying to make up for the fling by expressing her love for him.

"It's incredible not only would Kristen do this, but to do so in public beggars belief.

"Rob needs to get his head round it."

The 'Bel Ami' star is said to be particularly unhappy that his agent initially broke the news of Kristen's affair, rather than her telling him herself.

Another source told Reveal magazine: "It was like a bolt out of the blue. He was on his own when he got a call from his agent and there was stunned silence as he tried to take it all in.

"When he confronted Kristen about it, she didn't try to deny anything. She was crying and kept saying, 'I'm sorry.' "

Robert is believed to have returned to the UK following the shock news.