03/20/2013 at 11:00 AM EDT
Since they started dating last summer, Katy Perry
and John Mayer
have hit warp speed in the romance department: he's spent the holidays with her parents
, they've been house-hunting
, and he's surprised his girl
with some serious bling.
But lately, there has been a sudden halt to their happiness.
After a fun-filled getaway to his adopted home state of Montana in early March, Mayer, 35, and Perry, 28, and have been spending much of their time apart – even though they're within miles of each other in Los Angeles. The pair also broke up for a brief period over the summer.
When asked about the couple's split
, both of their reps had no comment. But there are clear signs the two are finished.
Along with keeping their distance over St. Patrick's Day weekend, Perry indicated she was in a particularly biting mood on March 15. The pop star Tweeted
: "Perfectly put, by Daughter" with a link to the indie-rock group's single "Landfill." That song includes the lyrics: "I want you so much, but I hate your guts I hate you."
Perry has also showed signs of unhappiness to those in her circle. "She gets really withdrawn when there's a change in a relationship," says a Perry pal, who points out that during a recent conversation with the singer, "she didn't mention [Mayer] at all."
For more details on the couple's troubled romance, pick up the latest issue of PEOPLE, on newsstands Friday