The Sky Sports presenter split from the Britain's Got Talent host after almost two years in April 2011.
The pair were said to have broken up due to Donnelly not wanting to start a family together.
She explained that, despite the fact that they are "done and dusted", they are still in contact.
"We are still in touch. We own a racehorse called Primeval together," she told New.
"It's all very amicable. I have started to get bored talking about it because we broke up a year ago. That's a long time.
"We both respect each other hugely, we have a great fondness for each other, but everything else is well and truly done and dusted."
Thompson was romantically linked with X Factor USA host Steve Jones following their break-up last year.