Joe Cheated on Taylor

Taylor Swift is laying it all out there, calling her ex-boyfriend Joe Jonas a cheater.

“[Joe and actress Camilla Belle] have been together for months,” Taylor tells OK!. “That’s why we broke up.” (Joe dumped Taylor over a 27-second phone call just last month. You do the math.)

It was reported yesterday that Joe, 19, has a new older love, 10,000 B.C. star Camilla, 22.

When asked if she and Joe are still friends, Taylor curtly replied, “We don’t talk.” (They haven’t talked since the break-up call.)