Walk the Line

Question: After John's arrest in El Paso, in the following scene he's talking with Viv about the incident and denying he has a problem, even though she says everyone around him says so. She then asks about June and he says she left the tour and Viv responds with "Well that explains everything, doesn't it?" What exactly does she mean by that statement?

Chosen answer: Viv's implying he is acting the way he is cause he is upset about June leaving.