If you notice, he was calling her his "wife" an awful lot in that video. I'm 90% sure there's more going on that we dont know about. He's about to convince this girl to marry him to avoid having to testify against each other.
UPDATE:
"Law enforcement sources tell TMZ, the alleged victim and NBA Youngboy were at his home when Iyanna arrived and told the woman, Lapattra Lashai Jacobs, she was Youngboy's fiancee and Jacobs should leave the house. Jacobs then told Iyanna to leave.
We're told the argument moved into the kitchen, where Iyanna was holding 2 knives. According to our sources, Jacobs stepped toward Iyanna and Iyanna charged at her with one of the knives. Jacobs told cops she didn't feel the first knife wound but then she said Iyanna charged at her with the second knife, stabbing her again.
When EMTs arrived, Jacobs was laying on the floor. She was taken to the hospital. We do not know her condition."