joseph: The right to divorce? Anyone has the right to divorce. You don’t need a halachic reason although their are halchachic reasons when a divorce is commanded.
As for my scenario above. The couple discusses the situation with a Rav. The therapist is given written permission to discuss their patient with the Rav. Upon hearing everything the Rav decides divorce is the best road. Don’t tell me that the couple does not have the right to divorce.