I agree that walking along the knife's edge can be erotic. It's important to distinguish between a finished game - where you know what you're going for, and can enjoy the tension knowing that it will ultimately resolve the way you like - and ongoing development. A finished game can have a lot of tension building, because the resolution is always in the story as well. With ongoing development and episode releases, I risk suggesting that unresolved tension can be more negative than positive.
A cliff-hanger flirting with ntr is enough to drive people away. Keeping it on, episode after episode, will make sure anybody whose support would depend on the final stakes, will never be on board, or jump ship at some point. A majority of those that remain would be those that support more extreme dynamics. If the story really were headed towards Vi finally caving into becoming a free use slut and making Erik a helpless cuckold, that trimming would just be natural selection, otherwise it sounds like keeping the mystery is high risk for low return.
I don't presume to give advise, it's just my personal opinion: while too many reassurances (such as "asking for permission" before doing anything) definitely become tiresome, keeping players in permanent doubt as to where the story will ultimately go could lose at least those who feel that supporting, investing time reading, and getting attached to characters is worth it, if in the future they can become completely unlikeable.
There seems to be a fine balance required, between teasing as far as you can, and assuring players that the compass is steady and the game isn't course correcting into where many won't go. Between avoiding spoilers, bringing up surprises, and letting people know where the game is going. I'm personally all in favour of the author writing exactly what comes out of their soul, and I've enjoyed this game entirely, as a kinetic story, up to the present. But if were ultimately planned to become a story about an MC letting go of any control over his relationship, so be it. Just let people know.
Having said that, I don't feel like a blowjob that wasn't given prior clearance to, meant the game was headed towards a whore gf, cuck bf dynamic. My humble 2 cents is that ending episodes in cliff-hangers of that sort is counterproductive. This entire comment is about ending episodes in such cliff-hangers. Let the flirting with losing control, which I agree can be erotic, happen in the middle of the episode - but let the situation be resolved in the same episode, one way or another. Tension and release.
Unless the plan is to really let rivals score at the expense of the mc. People who enjoy the tension when an episode ends in an ambiguous way, relative to the relationship between the main characters, are probably the same that will enjoy that. I bet most of those who enjoy teasing but not actual humiliation or emasculation of the mc will be annoyed if the game keeps signalling it might go there, even if that is not where it's ultimately headed.