"Planning for the worst doesn't mean I'm not hoping for the best."

He just knows not to expect it. What, does she think he likes the idea? Violence isn't something he means to encourage, but it's likely to be a fact of life, no matter what. It doesn't necessarily mean surrendering to fear and anger, even if it's likelier. All he can do is the best he can do.

"I can't protect him from everything."

That's not him making excuses. He wishes, desperately, that he could.