Gabor:
It is my m.o. to ask for details that I know wouldn't and shouldn't be part of a logline in order to get a better understanding of the concept, to, hopefully, provide useful feedback.
And I still don't have a clear, focused view of your concept. Your logline currently reads:
An estranged couple decides for a last-chance counseling retreat in a forest just to experience a therapy that turns into their worst nightmares.
Does that mean the couple are intentionally seeking a therapy that will force them to confront their worst nightmares? Or do they discover that the therapy forces them to confront their worst nightmares -- an unintended consequence?
And, again, what is their worst nightmares?
Maybe it shouldn't be included in the logline, but isn't EVERY plot (certainly in the horror genre) about a protagonist who MUST confront his worst nightmare, the one thing he fears most? Isn't that sui generis, the standard psychological dynamic of the modern dramatic formula?
So what differentiates this couple's nightmares from the 1,001 nightmares faced down by estranged couples in a 1,0001 stories about relationships on the rocks? What makes this story unique from the others?