"She added, "[And] it's nobodies fault it's just like I guess we grew out of love.
Fans are speculating that the breakup was Cardi B's decision, as Offset responded to her post with the cryptic comment, "Y'all won".
Baby Kulture's big reveal comes weeks after Cardi B explained exactly why she made a decision to keep her daughter out of the public eye. A lot of girls would just deal with this situation and be like, "Yo, like I took Cardi B's nigga" or 'I'm the reason they getting a divorce.' I feel ashamed.
The rapper had been teasing fans with peeks at her daughter for months, and had some - including Offset - convinced she was going to debut her daughter at the 2018 MTV Video Music Awards in August.
While speaking in a video likely recorded on her cell phone, Cardi B spoke about her relationship with Offset. In June, Cardi B revealed that they had been married the whole time, saying, "There are moments that I want to keep to myself". "I said I do, with no dress, no makeup and no ring!"
Cardi B has become one of the biggest new stars in U.S. music since the runaway success past year of her song "Bodak Yellow", which touches on her former life making ends meet as a stripper.
Cardi B and Offset are parents to daughter Kulture Kiari, who was born on July 10. You have low self-esteem.' I don't have low self-esteem ... "We are not together anymore". We're really good friends and you know we're really good business partners...
Alongside the video, she simply wrote: 'There you go, peace and love'.