john-katy-perry-split.jpgKaty and John after dinner on Valentine's Day

Katy Perry and John Mayer have split for the second time, according to Us Weekly.

Though multiple sources confirm that the two have broken up, one insider tells the mag, "It's not over until it's over. You have to see how things play out." Another added, "She's leaving the window open. They have both been so focused on work."

Katy and John started dating in June of 2012, but they ended their romance in late August, only to reconcile and get back together in September. In November they went on a romantic vacation to her hometown of Santa Barbara, and they seemed fine on Valentine's Day (see pic above).

Things seemed fine earlier this month too, as Katy tweeted on March 2, "My boyfriend is taking me to a kitten shelter in his truck. I can't think of a more perfect Saturday."

However, on March 10, she wrote, "Chiropractor, Therapist, a hike, and a psychic reading. Come on Monday, give me your best shot," and two days ago she added, "ATTENTION: Mercury is OUT of retrograde today. Thank GOD." Wonder why things went wrong ... and so quickly?