Holly Madison (left) and Crystal Harris
Jason LaVeris/FilmMagic, Mark Sullivan/WireImage
04/11/2011 at 07:10 AM EDT
The guest list at Hugh Hefner's wedding
has mostly been set, but there's one former flame who won't be in attendance
"I think Holly [Madison] has expressed publicly that it would be a little strange if she was there and I respect that," the Playboy
founder told PEOPLE at his 85th birthday party at Las Vegas's Palms Casino Resort.
As portrayed on E!'s Girls Next Door
, Madison hoped to marry Hefner but eventually moved on and relocated to Las Vegas. Hefner, meanwhile, moved on to 24-year-old Crystal Harris, whom he will wed on June 18. The feud between Madison and Harris
has been well documented.
As for Kendra Wilkinson and Bridget Marquardt, the two other women who costarred with Madison, they are invited, despite Wilkinson's recent claims that she has yet to receive a "Save The Date" card from the couple.
"She knows she's invited," Hefner said. "The invitations haven't gone out yet."
Hefner, himself, is a little surprised that he's taking another trip down the aisle.
"I never expected to get married again," said the previously twice-married
Hefner. "But the reality is I can't see myself with anybody else, and I just want to give the relationship that kind of formal statement. I think Crystal deserves it. I love happy endings."