Elton and David Furnish were having a good time in Australia until the latter suddenly became ill.
A source told Confidential that the filmmaker flew back to Los Angeles for treatment.
"David had various appointments and engagements set up during the tour but he's had to cancel them.
"Elton was obviously extremely distressed, and his first instinct was to leave the tour to be with his partner when he was ill.
"But he spoke to his old friend Michael Chugg, who is promoting the tour, and in the end they decided the tour - the show - should go on."
Elton and David, who tied the knot in a civil ceremony in 2005, had brought their young son Zachary for the tour, which began at Star Casino last week and moves to the Hunter Valley this weekend.
It was not known if Zachary flew home with Furnish or remains on tour with the singer.