"We are confirming that we have amicably separated," the pair said in a statement released May 22 by Richie's publicist, Cindy Guagenti. They did not provide any details of the breakup.
Richie, 24, and Goldstein, a professional club DJ who goes by the name DJ AM, called off their engagement in December.
The two were spotted together again a few months later, and Richie confirmed their couple status in an interview for the June issue of Vanity Fair.
Richie, the daughter of R&B crooner Lionel Richie, co-stars with ex-friend Paris Hilton in "The Simple Life."
The reality show moved to E! Entertainment Television after Fox declined to air a fourth season. A new format allows the feuding friends to have nothing to do with each other.