Robert Pattinson and Kristen Stewart's hot relationship is cooling down and Kristen’s pals are telling her that it’s because her boyfriend is a playboy with a wondering eye. “He loves the seducing and chasing part of the relationship, but then is quick to back away,” a source tells BettyConfidential.

And now, Kristen, 19, is picking up on the little things that Rob used to do, but doesn’t do anymore. “He used to run for the phone when it rang,” says the insider. “Now, he doesn’t even call her back right away. He plays it off that he’s busy working.”

Rob, 23, tried to reassure Kristen by saying, "I’m just busy. It has no reflection on our relationship.” But his actions are speaking louder than his words. And friends say when he’s out on the town, he scopes out the room and has no problem talking to — and flirting with — other beautiful women.

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It’s certainly a big difference to the way he acted last year, when he chased after his Twilight co-star for months. “Rob waited patiently for her as she was still in another relationship [with Michael Angarano],” the insider says. But now, the chase is over and Rob is in pursuit of another goal — furthering his career. “Work is coming first. His management is telling him he needs to stay focused.”