'Dancing with the Stars' ' Carrie Ann Inaba and Actor Robb Derringer End Engagement After 9 Months

Carrie Ann Inaba and Robb Derringer have quietly ended their engagement, a source tells PEOPLE exclusively.

Derringer, 50, proposed to Inaba, 49, in December and as recently as early August it appeared planning for their Hawaii wedding was moving along.

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But this weekend the Dancing with the Stars judge hosted an event for Olympic figure skater (and DWTS alum) Kristi Yamaguchi in Hawaii and wasn’t wearing her ring and had her mother — who was to serve as her maid of honor — by her side instead of Derringer.

Speculation of a split began on Sept. 7 when Inaba posted a cryptic Instagram post of a quote that read, “Just when I think I’ve learned the way to live, life changes.” She captioned the graphic of the quote with prayer hands and a broken-heart emoji.

“I knew after our first romantic date, that if she felt for me what I felt for her, then it was something that was going to be significant and life changing and lasting,” Derringer told PEOPLE when announcing their engagement. “There was just a powerful and palpable sense of destiny that I could not deny.”

“As a young girl, I had always dreamed about going on a date like the first date I shared with Robb,” Inaba added at the time. “Somehow, he instinctively knew what that was and went to great lengths to surprise me with the most romantic night ever. I could see then how pure of heart he was and how generous and caring his soul was.”

“Everything about the evening felt so ‘right’. There was an ease and an authentic familiarity,” she continued. “We talked about everything under the stars … even marriage. There was a strong sense of destiny that night, and I think I knew then, deep in my heart, that he and I were going to be together forever.”