Robert Pattinson is in Australia shooting his next movie "The Rover" and the distance has caused so much concern for Kristen Stewart that she flew there to be with him, according to a source.

Stewart, 23, is afraid the 8,000 miles between them might end their relationship for good and is worried that the British hunk will meet other women during his time spent in Australia

"She can't stand the thought of some woman getting her claws into him," an insider told Life & Style Wedneday. "He'll be gone a long time, and Kristen is upset. She's worried they won't be able to make their relationship work with the distance."

However, Stewart's insecurities are pushing her and Pattinson, 26, further apart. The insider said, "Rob wants her to stop being so needy and jealous. She's pushing him away more and more."

Conflicting rumors suggest that the Twilight couple already broke up. A source reportedly told Star, which published the story Wednesday, that Pattinson and Stewart have already split due to trust issues. He reportedly has yet to get over Stewart's spring fling in 2012 with married film director Rupert Sanders, who she worked with on "Snow White and the Huntsman." Pattinson now hopes he and Stewart can remain platonic friends despite the split.

"Rob really wanted it to work but he just felt like the trust was gone," a source told the magazine. "Neither of them seemed really happy and he just thought it was easier to end it for good. He was honest with her and said they had been through so much he hoped they could remain amicable.  

"Rob is really keen to keep everything civil and work on being friends. It would be too much to be completely without her because she is such a massive part of his life." 

Pattinson arrived in Australia on Jan. 17 without Stewart to begin a nine-week film schedule for "The Rover." 

source told Hollywood Life, "For Kristen, it's all or nothing. She's ready for marriage, but Rob is over the relationship."

Stewart was last seen with Pattinson at an exclusive VIP Golden Globes after party thrown by the show's co-hosts Tina Fey and Amy Poehler.