Her husband was right. Perhaps it was better to lay it all out for their son, tell him their side before he had the opportunity to hear less than truthful information from outside sources. Likely he'd already learned more about his parents in just his single year of schooling than he had all of the years of his life prior. Away from their parents, children would've been more comfortable sharing what they knew. Oliver could've been hearing nothing but lies. The moment would come soon where they would have to tell him just about everything. Some details of their actions they would take to their graves. Probably best to do it before he went back to Hogwarts for his second year.