1. Anthony has affair with Mary. Then, she realizes he’s married, they get into the fight (as seen towards the end of the movie) and later they have a car crash. He survives the accident, however gets injured. That’s how he got scars. Helen, of course, finds out that he had been in an accident with a woman he was having an affair with, however she forgives him. There is a clue that Mary survived the accident as well, which will be mentioned later.
  2. Anthony tries to carry on with his life, but it’s difficult. On one hand, he’s overwhelmed with guilt, on the other, he’s not ready to give up his former lifestyle (which is chasing other women, as his mother mentioned).He starts visiting sex clubs and that’s how he tries to conquer his problems, but not permanently. Notice how a spider is stepped on and crushed in a club scene. I believe spider represents his fear of life with Helen and becoming a father.
  3. However, the fear (along with possible guilt) reemerges and he needs to deal with it some other way. That’s when he creates an alter ego – Adam, a college professor. He probably looked up colleges and ran into Adam’s name and unconsciously “decided” to use that name for his new personality. A professor named Adam Bell indeed exists, however when both Anthony and Helen look him up, they find only the name, no pictures. Therefore, he could be anyone.
  4. Notice how most of Adam’s life (which takes place only in Anthony’s mind) is somewhat surreal and empty. He teaches the students same lesson twice (at the beginning of the movie) and once he even walks into the empty classroom. Classes shown at the beginning take place in Anthony’s mind, however, walking into empty classroom indeed happens, since later he runs into Helen. I believe empty classroom is meant to show us that he does not teach at the university.
  5. Through Adam, Anthony tries to detach himself from his real life. Notice there’s only half of the whole picture, which is later shown in his and Helen’s apartment. As Adam, he symbolically cut off Helen from his life (therefore, the torn picture) and has a relationship with Mary. However, the pieces of his real life start popping into his consciousness while he’s in his “dream world” as Adam. That’s why Adam’s friend (who is also figment of Anthony’s imagination) recommends him to watch the movie. That’s when the imaginary world starts to collapse.
  6. Helen notices there’s something wrong with her husband. At first, she thinks he’s having an affair with Mary, AGAIN. That’s what makes me think that Mary survived the accident, as well. Helen gets suspicious, looks up the alleged professor and decides to pay him a visit to find out whether he was a “jealous husband”. When she arrives at the university, there is a shocking revelation. She runs into Anthony, who was, at the time, completely overtaken by his alter ego. She’s upset, which is shown in later scene where she says something like: “I think you know what’s going on.” She is not sure whether Anthony has a mental illness or he’s playing a trick on her.
  7. Anthony is unaware of his condition and meets up with Adam. The meeting, of course, takes place in his head, therefore the isolated motel. Adam, who is about to get destroyed (since Anthony will possibly find out he’s just an alter ego) suddenly withdraws from conversation, therefore allowing Anthony to carry on with delusion.
  8. Anthony now wants to stay with Helen, but to have an affair Mary as well. That’s why he insists on taking Mary to a romantic holiday. Instead of it, he returns to his and Helen’s apartment, but this time as Adam, since his alter ego had overtaken him. Helen notices he’s being awkward and wants to find out whether he’s into Adam’s character again. That’s why she asks him: “How was school?”. Now, she’s certain of his mental condition. He falls asleep and has dreams of his accident with Mary. When he awakes, he realizes that something’s wrong with him, breaks down and cries. Helen shows him support and asks him to stay, meaning she liked Adam personality better than the original.
  9. For a while, everything seems to be in order. Next morning, he hears about some accident, but turns off the radio, since it reminds him of the one he had. Now he becomes a dictator, who censors the information. When he finds the key for club, he switches into his old self and his fears of fatherhood (and perhaps women in general reappear) and that’s why he sees Helen as a giant spider. That’s the moment when history repeats itself. His fear of the women may have been caused by his relationship with mother, who seems to be somewhat distant and shows little understanding for his problems.