Sam and Dylan were competitors for Sophia's favor from the beginning. Dylan was always shown as jealous when Sam tried to get close to Sophia in his presence. What you describe is a Dylan at the end of the cuckold path. Who is already conditioned to get sexual arousal out of his jealousy and humiliation.There are so many possibilities, especially for Dylan as an observer of the event between Sophia and Sam, that would not have had to end in blackmail. The crucial point would have been that Dylan get some more knowlege about what Sophia is already doing outside her marriage to get his story make some progress. It would also be the cuckold path, just with more connection between the story lines, what would normaly be considered a good thing for story telling. The event with Sophia, Claire and the new character is just a less involved version of that, with the new charkter as replacement for Sam. It is the same idea just at a much slower pace.
One possibility would have been if L&P had reversed the order of the updates. If Dylan had seen the slow progess event in the salon first, he would have been much better prepared to observe the event between Sophia and Sam. It would have been a voyeur event based on his kink that he became aware of in this update. With the actually implemented solution, once again months have gone by without much going forward in the story. After more than five years in development, this is simply way too slow.
The Dylan he is now in the story, also because he is just self-affirming in the success of his courtship of Marie, would react quite differently and not at all submissively. And there it makes in my opinion no difference whether L&P Dylan would have seen the event in the salon first.
The point of view of my argument is the state of history now and not a completely different set-up much earlier that you may have in mind.