The "I Want Candy" singer announced his split from Martin on Twitter Tuesday after nearly two years together, and one week after the birth of their son Prince.
"Due to personal reason[s] Melanie Martin and I have decided to go our separate ways," he wrote.
Carter, 33, alluded to "a very big lie" that took place between Martin and Carter's estranged twin sister Angel, but did not offer specifics, only noting that he believed Martin had "been lying to me the whole time." (Martin declined to comment to PEOPLE.)
Angel had a domestic violence restraining order against Carter extended in 2019.
Aaron Carter/Instagram Melanie Martin and Aaron Carter
"I can't even shed a tear. I'm in utter shock," he wrote in additional tweets. "I don't have a family now. I was deceived and lied too [sic]. I can't believe she betrayed [me] this way. I gave her the world. There's more to the story then [sic] meets the eye. My Heart hurts broken heart."
"Prince doesn't deserve any of this and now it's my job to just be a single father and that's what's gonna happen," he wrote.
Carter and Martin made their relationship Instagram official in January 2020, and announced their engagement that June.
On Nov. 22, they shared news that their son Prince had been born following 13 hours of labor and an emergency C-section.
"Prince is precious I love you son. Your mommy loves you as I drop tears on the phone," Carter wrote on Instagram, along with a video of him cutting the umbilical cord. "@missmelaniemartin I'm so proud of you hunny you did it."
He added, "I Love you with all my heart my beautiful blessings from god."