A hard conversation goes better when you’re in it, not rehearsing your next line.

Rehearsing during a difficult conversation feels like preparation and functions as absence. While you are assembling the next sentence you are not hearing this one, so you respond to a version of what they said rather than the thing itself, and they can feel it happening. Then they start rehearsing too, and now two people are talking past each other very carefully.

Drop the script and accept a few seconds of silence before you answer. It will feel like losing and it is not. Ask one clarifying question before you defend anything. Most conversations go badly because neither person was actually present for it.