"Taylor trusts Calvin more than anyone she's ever met. He promised her he'd never break her heart, and she believes him."
The two recently shared several snaps from the July 4th holiday weekend - one photo featuring Swift kissing Harris on the cheek - and have gone on a double date with Swift's ex Joe Jonas.
No word yet on where they are moving to, though Swift currently lives in a Manhattan apartment. According to the magazine, she let Calvin stay there for three nights in a row back in May - a huge step for the normal unlucky-in-love celeb.
Taylor Swift has been through a number of public break ups with the likes of Joe Jonas, John Mayer and Taylor Lautner, while Calvin has had equal heartbreak with Rita Ora.