The news comes 10 months after Katya sparked a media storm when she was photographed kissing comedian Seann Walsh, her celebrity dance partner on the 2018 series.
The couple – who had been together for 11 years – said in a joint statement that the split was “mutual”, both pledging to “keep working and dancing together as well as exploring individual projects”.
"We wish one another every happiness and we will remain the best of friends," they said.
"We are really looking forward to getting back to the ballroom and can't wait to keep on dancing."
A spokesperson for the couple said the split wasn’t only influenced by the kiss between Katya and Seann. “It would be incorrect and unfair to attribute their separation to one isolated incident," a spokesperson told RadioTimes.com. "Many people make such a decision to separate when they realise that their relationship has become more of a friendship. They remain the very best of friends and will continue to dance together.”
After photos of the kiss circulated in October 2018, Katya wrote on Twitter: “I’m so sorry about any offence or hurt I may have caused with my actions. I wasn’t thinking and it was a one-off mistake after some drinks. I love my husband and we are very happy together, this is not a reflection on our relationship.”
Earlier this year, the pair performed their own dance show that charted the “ups and downs” of their relationship.
Speaking at the Radio Times cover party in January, Neil said: “It’s basically a story about myself and Katya, how we met when we were younger and all the way until we became world champions and the struggles of a dancer to get to the top.”
Strictly Come Dancing 2019 starts this September