What the hell? The woman took his kids and somehow he's a monster because he called her a bitch?
-- Anyway, I didn't say his used of "bitch" proved anything. But I've seen enough people in abusive relationships to know that it's a clue. The fact that he would illegally (and surely, contrary to company policy) abuse his position as an AT&T employee to stalk her further clarifies the picture.
But NATURALLY, they're his kids because it was unspecified and you identify with the father, and because them being his kids makes her a bitch. Now it's internally consistent!