Kristen Stewart & Robert Pattinson at the 'Breaking Dawn' premiere

The 'Twilight' hunk - who ended his four-year relationship with the brunette beauty in May following her 2012 extramarital fling with director Rupert Sanders - was spotted leaving her home in Los Angeles, California, on Sunday (04.08.13), where he reportedly tried to clear the air and assured her that he is not dating her 'Runaways' co-star and good friend Riley Keough.

A source told "He doesn't want to be that guy. He doesn't want the image of him being that he is stealing the friend in the wake of the relationship with Kristen.

"Rob did tell people that he reassured her that he wasn't going to date her friends and make things more awkward between them, because the breakup is and has been awkward enough."

A friend close to Kristen, 23, revealed that she enjoyed spending with Robert over the weekend but they don't have time to work on their relationship at the moment so they are trying to be friends.

The insider said: "Rob initially reached out to Kristen because he wanted to stop by and pick up the rest of his stuff, but apparently he also wanted to see her.

"He stopped by on the weekend and they both spent some time together, catching up. Kristen was really happy to see him, but I think in the end they were both sad because they still have feelings for each other. It's not as simple as just getting back together. Seeing each other brought up lot stuff for both of them. For now, work -- not rebuilding a relationship -- comes first. It's sad."

But Robert, 26, hasn't given up hope that he and Kristen might have a future together.

A source said: "He's told his friends that during a different time and different circumstances, they could make it work."