The alleged cheating incident took place in March, after Ali flew to Los Angeles to visit her then-boyfriend Grant.
Earlier this year, Grant spoke exclusively to New Idea about the alleged incident.
Grant revealed he called time on heir relationship after he caught Ali in a passionate tryst with his best friend – in his own home – just days after she landed in LA to start their new life together.
Ali has previously described Grant's accusations as "horrible", but has not denied them.
He told New Idea, "The third or fourth day she got here, we went out and this night – when all this stuff happened – I had people over after going out to a club. I live in a gated community so I have to go down and let people in sometimes.
"So, I leave my house with my friend Sabrina, to go and grab my friends and bring them back upstairs, and when we walk back inside, we come up the stairs and she is hooking up with this dude."
The text message exchange has not been confirmed as Ali and Grant.