"When I met your mother again, she'd already been through something very difficult. I thought, at the time, that she was happy, and I should have pursued her the moment I met her instead of waiting. Sebastian married her, but the marriage was never real, the registration was fake, and your mother didn't know it. He then married someone else in secret, and he kept that hidden from your mother the entire time they were together. When she finally found out, she left."
He paused, glancing at each of their faces in turn, gauging how much further to go.
"That's not the whole story. It's more than I can tell you right now, and some of it isn't even mine to tell. But your mother went through hell getting that man out of our lives afterward. That's why his name isn't spoken in this house. Is that okay?" He stood, some finality in the movement, clearly done with the conversation whether they were or not.
"Now hurry up, all of you. You'll be late for school."
