Credit: Naomi Kaltman/UsWeekly

Taylor Swift, who's dated Joe Jonas, Taylor Lautner and Glee's Cory Monteith, is famous for kissing, crying and telling -- in song, at least.

"Every person I've fallen for, they've all been a song," the star, now 20, tells Us Weekly in Taylor Swift: Inside My World, a special collector's issue hitting newsstands Friday and on presale now. Swift says she's "proud" of those songs. "That kind of justifies [the exes] being in my life."

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One of those rumored exes, John Mayer, is the speculated subject of "Dear John," an angry new song from forthcoming album Speak Now. In the track, Swift sings, "Don't you think nineteen's too young To be played By your dark, twisted games When I loved you so."

The star hasn't confirmed whether Mayer, 33, is the song's true target, but tells Us that some boys are scared off by her deeply personal music.

"Guys will say something like, 'Oh, I'd better never make you mad because you'd write something about it.' Or, 'I don't want to be one of those guys,'" Swift admits.

"But I've always lived by the theory that if a guy doesn't want me to write a bad song about him, he won't do bad things," she says. "And he shouldn't, you know?"

But Swift insists she's not looking to settle scores or avenge her exes via music, either. "I just write from my perspective about how it ended up and what I felt about it," she explains.

Pre-order Taylor Swift: Inside My World now -- full of exclusive pics from her scrapbook, details on her deluxe new home, never-before-seen childhood pics and much, much more.