Fashion Police co-host Kelly and vegan chef Matthew confirmed that they had called time on their two-year relationship this week in a joint statement.
Speaking to Giuliana Rancic on E! News, 29-year-old Kelly said: "It was a mutual decision. We love each other very much. It just wasn't the right time for us, and I think if we weren't as mature and adult than we are, then we could have gone down a road that wasn't really nice."
Matthew proposed to Kelly while they were on holiday on Caribbean island Anguilla in December 2012, but the pair kept it a secret, only publicly announcing their engagement in July last year.
Kelly, who met Matthew at supermodel Kate Moss' wedding to Jamie Hince in 2011, continued: "We're still really, really good friends; it's just we're not living in the same house."
Kelly's mum Sharon has also commented on her daughter's split while appearing on Thursday's episode of her chat show The Talk. Sharon, 61, said: "Matthew is a lovely guy. They had two great years together of fun and love, and for me, that's why engagements are so important."
Before meeting Matthew, Kelly was previously engaged to British model Luke Worrall in 2009, but they split a year later.
Got an iPad or iPhone? Reveal Mag has been especially designed to fit!