If this was a real world scene and they hadn't negotiated or discussed bringing in those feelings to the play, yeah this wouldn't be okay. Whether it would be emotionally manipulative would depend on a bunch of nuanced interpersonal stuff but it would definitely be something that the people playing should talk about afterwards.
But in terms of a kinky horny fun scene, I think it all depends on the individual reading it. If you're taking this series seriously and looking for something more realistic and consent heavy, it totally makes sense if these past chapters have made you uncomfortable. But if you're focused on the fantasy of it all and fill in the blank that they're both fully aware and consenting to this dynamic, I think this scene is super hot and fun. But that's just me personally. There's no right or wrong way to feel about how these chapters played out in the fictional world of this series. It all comes down to your personal preference, if you're able and wanting to suspend disbelief to prioritize sexy time, and if you want to seek education to understand how the fantasy and the real world are different.
If you have any questions regarding real life kink/ BDSM, I've been involved in the kink scene for over 10 years and I've been a demo bottom and an active kink educator for more than half of that. I'm happy to share what I know and I respect however you personally feel about this series. I just hope that you can allow yourself to get curious and enjoy the parts you enjoy without shame.
Now, I dunno much about bdsm, so I can't speak for the community l, but to me, the last two chapters kinda border on emotional manipulation? Like, why are we dragging personal issues into a PLAY where your partner is vulnerable and basically at your mercy