I'll tell you right now, what she's going to say is "I can't believe you don't trust me!" -- or some variation of that.
Your response should be "I'm sorry you feel that way; I did waht I felt I had to do to protect myself and our son."
In fact, that should be your response to pretty much everything from "I can't believe you didn't trust me" to "Now you've REALLY blown it!" to "How 'bout them Yankees this year???"
Stick with the script, Tristan. For talks like these, it's truly "Less is More."