By the way, she paid more.
The mother's explanation was correct, but she also spoke up for another reason. You may already know that many airlines charge extra if you want to book more than one seat in a row. This is important for families with kids, and they are willing to pay for the chance. But it wasn't cheap for this mother of three to pay extra for each seat. She didn't want to move her family's seats to make room for people who had paid the standard price.
Can't tell when to stop.
Once the man found out about the extra charge, you'd think he'd say sorry and be quiet for the rest of the flight. Instead, he kept saying that the couple shouldn't be kept apart, even though there was a very easy way to solve the problem. Even worse, he turned to the boy and kept asking him to switch seats with the husband. The man didn't know when to stop, and the mother's anger grew as she realised this.