Audrina Patridge and Ryan Cabrera -- whose brief relationship was shot for the last season of "The Hills" -- are dunzo.
According to EOnline, the reality star and the serial-celeb-dater broke up ... and it's a "touchy subject" for Patridge.
FYI -- Audrina didn't look too devastated when we got her hosting a pool party in Vegas this weekend all by her lonesome.
No word on whether the break-up was unscripted.
