Trivia: On the first day, Dominic West (Jasper) was asked by the script supervisor, "Are you an alcoholic?" Well, Dominic thought to himself, "Crikey," then he felt incredibly self conscious, and so he replied, "Yeah, probably." Then the script supervisor said, "No, no! I meant your character."
Trivia: As demonstrated in the film, Equine therapy is really used in quite a few drug/alcohol rehabilitation centers in the U.S. It's used to reveal things about the patient's personality and what they do in frustrating situations. (00:37:25)
Answer: He was a hard drinker who did not take her sobriety seriously, and she realised he was not good for her.
Brian Katcher