I think one of the biggest problems with this development is that this type of plot twist should belong in an entirely different genre of storytelling. This is sort of classic Greek tragedy, almost like a meditation on fate. But it requires an actual tragic (or at least bad) ending, which we all know won’t happen.
In the absence of any real risk — because I’m pretty sure CS is a foregone conclusion — there will be no long term consequences, and therefore the whole thing feels like cheap pointless melodrama that will be unsatisfactorily resolved, and won’t lead to any significant character growth.
In the meantime, depending on how much they want to wring out of this situation, I am actually going to bet one cookie on a temporary break-up — undertaken by Hook because he “doesn’t deserve Emma.” The rest of the drama will be about Emma trying to assuage Hook’s guilty conscience induced manpain. Which has been their MO since the get go, and since the audience seems to love it, why mess with a good thing?