Robert Pattinson was going to propose before Kristen Stewart cheated

Robert Pattinson was "weeks away" from proposing to Kristen Stewart before finding out she cheated on him.

The 'Twilight' star was due to ask for the brunette beauty's hand in marriage in the spring and he had even bought a £5 million Los Angeles mansion for the couple's future before being told of the 22-year-old star's affair with her 'Snow White and the Huntsman' director Rupert Sanders, 41.

A source told the Sunday Mirror newspaper, “Robert hoped to marry Kristen and was making preparations to spring a proposal before she admitted cheating. He had bought the house in Los Angeles to be their home and saw them staying there for a long time."

But since discovering the news, Robert – whose character in The Twilight Saga: Breaking Dawn – Part 1 married Kristen's alter-ego onscreen last year – is "angry" with Kristen and the 26-year-old hunk has moved out of their LA home.

The insider added, “Now Rob is angry – he’s left the mansion and not spoken to her since. They have exchanged heated text messages only.”

After pictures of Kristen and Rupert together emerged, the pair publically confessed to cheating on their respective lovers, and the director has "apologised profusely" to his model-and-actress wife Liberty Ross – who played Kristen's mother in Snow White and the Huntsman – in the hope he can save his marriage.

A friend explained, “Liberty is hurting. But she’s realistic. Things happen and marriage isn’t easy – she just hates the fact her name’s been dragged into all of this. Rupert has apologised profusely and she has accepted his apology. She hopes things get back on track – after all, they have kids together.”

Robert now wants to have a one-on-one chat with Rupert to find out "exactly what happened" between the filmmaker and his girlfriend.

A source said, "Rob wants to have a man to man chat with Rupert to find out exactly what happened between him and Kristen.

"Kristen has already betrayed his trust by cheating, so he can't be sure that she will tell him exactly what went on between her and Rupert."

Robert and Kristen are contractually obliged to be pictured side by side on the red carpet at the premiere of their final Twilight movie together, The Twilight Saga: Breaking Dawn – Part 2, later this year.