or just use this to make Ai feel guilt and anxiety so she won't leave?
100% this.
If you re-read the first few chapters, you'll see that Kaede did prey on Ai. She is a predator, using any mean she see fit to catch her prey.
That chapter was pretty good. I'm glad to see that Ai is, at least for now, staying faithful to Kon. I know lots of people are blaming her for leaving Kon behind, but not getting closure in a relationship that was very important can haunt you up for decades... I do hope she see through Kaede's manipulation and calls her on her bullshit, but the poor girl is only 20, and is dealing with a crazy woman whom she was deeply in love with... Not the best combination to take the best decision.