Before I Go to Sleep — Ending Explained

The central revelation of the film strips away every pillar of Christine's presumed life. The man she believes to be her husband Ben is actually Mike, a former lover with whom she conducted an extramarital affair years earlier. When Christine attempted to break off the affair to remain with her legitimate family, Mike beat her violently in an airport hotel room and left her for dead, which caused her severe neurological damage.

Following the attack, Christine's genuine husband, Ben, cared for her until the emotional strain proved unbearable, eventually placing her in a specialized care facility. Mike, consumed by obsessive infatuation and refusal to let her go, exploited her daily memory wipes by posing as Ben, discharging her from the facility, and keeping her isolated in a suburban house where he maintained complete control. When Christine eventually pieces together the truth through her recovered memories and clues provided by Dr. Nasch and her friend Claire, Mike attempts to murder her once more in the same hotel setting. Christine manages to incapacitate him, surviving the ordeal, and is ultimately reunited in a hospital with her real husband Ben and their teenage son, Adam.

While the film resolves its plot as a literal psychological mystery, critics have highlighted two distinct readings:

• Metaphor for Chronic Domestic Trauma: The amnesia cycle operates as an allegory for real-world domestic violence, where abused spouses often compartmentalize trauma, repeatedly attempting to normalize their domestic environment after each traumatic episode in hopes of survival.
• The Sentimental Escapism Reading: Some critics have scrutinized the tidy hospital reunion at the end, suggesting it borders on psychological wish-fulfillment; in this view, Christine's psyche constructs an idyllic reunion with her long-lost son and true husband as an internal emotional sanctuary following catastrophic physical and mental violation.