The pair released a statement to MailOnline confirming they have ended their relationship, which began in 2013.
It read: "After careful consideration, we have decided to amicably end our relationship. There is no one reason for the failure of our relationship. Unfortunately it's just the way things have turned out and it's no one's fault.
"In the interests of our family we remain good friends and we hope that people will respect our privacy at this time."
Atomic Kitten star Natasha, and 5ive member Ritchie have been together since 2013 after they were reunited on The Big Reunion. The pair had first got to know each other from the music circuit back in the day, after both being in bands at the same time.
Their daughter Ella Rose was born in September 2014, and six months later they revealed they'd moved in to a new home together, along with Natasha's children from previous relationships Josh, Harry and Alfie.
Shortly afterwards Natasha revealed her hopes that her relationship with Ritchie would last "forever" and admitted she'd never been as "happy and secure."
"I hope with all my heart this time it's forever and the happy-ever-after ending I've always wanted," she said "I don't think I've ever been as happy and secure."
Natasha and Ritchie first announced their engagement in October last year. Ritchie shared the news with fans on Twitter: "So yep, popped the question and @NatashaOfficial and I will be getting a bit married." Natasha wrote on her feed: "So.....our news is now out! @RitchieNeville asked me to Marry Him."
During a romantic trip to Rome, Ritchie had popped the question, presenting Natasha with a gorgeous diamond ring. She later showed off her new accessory on Twitter and told Reveal Ritchie had picked the "perfect" ring for her.
She said: "I was blown away when Ritchie proposed to me, it was such a romantic moment."
Ritchie, meanwhile, gushed: "It was an emotional moment when I proposed in Rome and I was relieved Natasha approved of the ring choice!'
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