Appearing on This Morning, the 38-year-old football star spoke candidly about welcoming Kate into his life after the sad loss of his wife and mum of his three children, Rebecca, who passed away after a battle with cancer in May 2015.
'I'm happy again, and in a relationship and it's going well,' he confirmed, adding that reality star Kate had had a 'positive effect' on the lives of Lorenz, 11, Tate, nine, and Tia, six, as well as his own.
'The kids are also happy, they deserve to be after going through tragedy in the last few years of their life. There's not been one stage of going into this relationship where they've not been involved,' he continued.
'As long as they feel they are involved and in the conversation I think there's a chance they can reach happiness.'
Rio and Kate, 26, were reported to have started dating at the beginning of 2017, with The Sun stating that the couple were 'getting close' as early as January, but have largely kept their relationship out of the limelight.
However, they have given fans a few glimpses of the times they've spent together by sharing snaps on social media, including a series from a holiday they took this summer.
Earlier this month, Kate revealed that she was leaving her former showbiz life to focus on a more private life with the sportsman and his kids, saying during an interview with the same paper: 'I'm taking a step back from the public eye, I want to keep my life private as I lived my previous relationship on TOWIE, my priority right now is Rio and the family.'
Rio is currently promoting his new book, Thinking Out Loud: Love, Grief and Being Mum and Dad, which recalls his own experience of loss and offers advice for others going through similar stages of grief.