After nine years together, the couple – who share five-year-old son Xavier - called it quits soon after the season wrapped and sold the house they renovated on the show together.
Taking to Instagram in early 2018, Kate revealed the sad news to her followers, though it is believed they went their separate ways in November 2017.
“It is with great sadness we share that Harry and I are no longer together,” she wrote.
“Over the last few months we have been making this transition process as smooth as possible for our little man.
“We are both committed to co-parenting Xave, with his wellbeing as our number one priority.”
Despite the pair’s on-screen clashes, Kate insisted to Adelaide’s The Advertiser that House Rules wasn’t the catalyst behind their break-up.
“We’ve been working on our relationship for a while – it’s not something we gave up on,” Kate told the publication.
“We just drifted apart. That happens sometimes I think, especially when you get together at such a young age.
“The experience we had on the show didn’t surprise me in terms of having ups and downs so I don’t think it made a difference at all (to our relationship). I’m certainly glad we did it because we’ve got so many opportunities out of it.”
Months later, House Rules judge Laurence Llewelyn-Bowen doubled down, claiming the show had nothing to do with their relationship breakdown.
“I'm sure it wasn't us who split them. I felt they got on well during production,” judge Laurence told TV WEEK in May 2018, though he acknowledged the experience can be intense for couples.
He added: “But experiences like this can often bring people together. I've been married a long time, so it's not news to me that you can go through bad patches. And sometimes, you don't get on for days, weeks or months.”