Playmate Harris was scheduled to exchange vows with Hefner on Saturday (18Jun11), but she called off the nuptials on Tuesday (14Jun11) and parted ways with the publisher.
She spoke on Ryan Seacrest's American radio show on Wednesday morning (15Jun11) to reveal her reasons for the shock split, saying, "I called it off because I didn't think it was the right thing for me to do... For a while I've been having second thoughts about everything. I haven't really been at peace with myself lately. I didn't think it was really fair to him."
Harris told Seacrest she still wants to be friends with Hefner, but the publishing mogul has no idea what prompted the blonde beauty to leave him.
In a series of posts on his Twitter.com page on Wednesday, he writes, "Crystal did an interview with Ryan Seacrest this morning to explain everything, but I still don't have a clue.
"I didn't see any of this coming, but I'm glad things went wrong before the marriage instead of after. Live & learn."