The "Twilight" mega-stars called it quits Saturday after growing distant following Pattinson's return to Los Angeles from New York on May 8, People reported.
"They again went from spending every second together, to spending more time apart at their separate houses," a source told the mag. "Kristen has been in a terrible mood, and it was obvious that things were not great with Rob."
All seemed well in their relationship last April when the couple celebrated Stewart's 23rd birthday with friends and the two spent time together at the
E! reported that the "priorities" were at the root of the breakup and that the split was likely temporary.
A shift in the relationship came when Pattinson, who turned 27 on May 13, celebrated his birthday without Stewart, opting to celebrate his at his house with his friends instead rather than reveling in a lavish birthday his girlfriend planned for him, according to Us Weekly.
The actor has also reportedly moved his things out of Stewart's $2.195-million house in Los Feliz on Sunday, Radar reported, taking back custody of the two dogs they shared.
Stewart, 23, is said to be "heartbroken" over the whole thing, spending all her time at home and surrounding herself with friends around the clock.
Last summer, their relationship ended after it was revealed that Stewart had cheated on Pattinson with her "Snow White and the Huntsman" director Rupert Sanders. Their indiscretion came to light when they were photographed getting hot and heavy during a "marathon makeout session."
Sanders' wife, Liberty Ross, filed for divorce this year.
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