"Even though she made a horrendous mistake, Rob can't just switch off his feelings. He was madly in love with her and I think believes that it was a moment of stupidity, not a long, drawn-out affair and it'd never happen again.
"In Rob's eyes, Kristen was seduced and she's clearly not just sorry but completely destroyed by what she's done."
However, if the Cosmopolis star does agree to making another go of their relationship, he wants to establish some "ground rules" with Kristen.
The source continued to LOOK magazine: "If Rob decides to take her back, he'll have some ground rules.
"Kristen would have to spend more time in his home town of London. He also would want them to adopt the Angelina Jolie and Brad Pitt way of working - where they take it in turns to do a film so they can be around for time together."
- Bang! Showbiz