The 27-year-old Gold-medallist – the sixth celebrity to be voted off the BBC dance contest in 2021 – has a 23-month-old son George with Eirianedd Munro and apologised to her for "letting you down".
Peaty announced on social media: "Eiri and I have decided to go our separate ways.
"We have enjoyed a wonderful three years together, two of those with our gorgeous son George. Our priority has always been to provide the happiest and healthiest home environment for him, and right now that means ending our romantic relationship.
"I could not ask for a greater mother for George and I am so grateful to Eiri for her amazing support over the last three years. Eiri and George, I’m sorry for letting you down.
"My only interest is for the well-being of our family at this difficult time so I ask that our privacy is respected and I won’t be saying anything further."
The swimmer from Uttoxeter, Staffordshire met Munro when he was training at Loughborough University where she was a student.
Peaty was partnered with Katya Jones for the 19th series of the celebrity dance show and spoke out on the consequences of the Strictly curse rumours following speculation that he "almost kissed" Jones at the end of their passionate Argentine Tango.
He tweeted at the time: "To everyone who wants to see what they want, your comments have real life consequences. I will not be overcome or lowered by your gossip. Protect your energy."
Munro made fun of the speculation that Peaty had been about to kiss Jones on live TV with a video posted on TikTok.
In a parody video she pretended to cry to camera, writing: “Watching your boyfriend almost kiss another woman on live TV.” She then threw her head back dramatically adding: “Finding out 10 million other people also watched it live.”
After Peaty left Strictly he confessed he was "not okay" following his stint on the show.
He admitted the pressure of the show got to him, which he joined almost immediately after returning from the 2021 Tokyo Olympic Games in July.
Peaty said: "I don’t think it was the dancing that pushed me over the edge, but the two years of the constant challenge with myself combined with the energy to win the Olympics and becoming a father at the same time. My emotions are one of my strongest attributes and I’m not ashamed to show that I’m human."
The Strictly Curse has become almost as famous a part of the show as the dances and costumes, with many a celebrity contestant falling for their pro dancer partner over the years, or seeing their relationships break down after taking part in he series.
Watch: Adam Peaty's girlfriend reacts to that 'almost kiss' on Strictly