In Ninja girl's case, it was completely that Man's fault.So that flashback might be the most awkward build up for another shitty NTR situation I have ever seen. It's the ninja girl all over again
He kept rejecting her, and she found someone new and now he is crying.
Here, the Slave Trader isn't like that though. He isn't interested in the Dancer Girl.
So, if any NTR situation occurs it's from the Dancer Girl's perspective.