“In my defense” is a phrase worth catching yourself saying.

Certain phrases are a signal that you have stopped listening and started building a case. They arrive right as somebody tells you something hard, and they move the conversation from what happened to how reasonable you were. What follows is often true, which is exactly what makes it so useful for avoiding the point.

When you feel that move coming, stop the sentence and ask a question instead. Something like what did that feel like, or what should I have done. You can give the context later if it still matters, and often it will not.