The source added: "Shera Berchard, Hef's number one girlfriend, moved out as soon as Crystal moved back in."
It is unclear if the wedding will be rescheduled but insiders say not to rule it out.
The source said: "Never say never where Hugh Hefner is concerned."
Speaking after she backed out of the wedding last year, Crystal explained she knew it wasn't the right step for her.
She said: "I got cold feet. Over time I just realised it wasn't for me, it was all happening so fast
"I actually spoke to Hef about it before I left and we both came to the decision that getting married wasn't the best for either of us."
Crystal also admitted they didn't have sex very often.
She said: "There was couch cuddling, movie nights. Hef's like a big kid."
Asked if the relationship was physical, she added: "In the beginning, but after a while it just wasn't the most important thing to him."
- Bang! Showbiz