"It's happened before." She put her hand on his shoulder, then took it away. "I'm so frightened for her. But she says it's what she wants.""Hell, Mary. You know what this is. The son of a bitch was her goddam teacher.""Listen to you - what are you saying about her? Listen to what you're saying about her. That's our daughter you're talking about. You might at least try to give her the credit of assuming that she's aware of what she's doing."They said nothing for a few moments."Who knows," Ballinger's wife said. "Maybe they'll be happy for a time."He'd heard the note of sorrow in her voice, and thought he knew what she was thinking; then he was certain that he knew.
What I believe is revealed about the mothers and fathers relationship is that it is stressed to its limits. This is first revealed when the fathers inner monologue mentions how he has to tell his daughter that he and her mother are separating. This already shows how bad their relationship has deteriorated, but when the father is questioning the mother about their daughters decisions as seen by "Hell, Mary. You know what this is. The son of a bitch was her goddam teacher." it shows how not only how angry the father is, but how spiteful he can be. In the following line "They said nothing for a few moments." shows that there was nothing more to be said and that their relationship was on its last legs.