Fight fair. No bringing up old stuff, no audience, no low blows. You’ll still be friends after.

Arguments have rules even when nobody states them, and the rules are mostly about what you leave out. Dragging in things from two years ago, doing it where people can watch, going for the spot you know will land, all of it wins the moment and costs the relationship. A fight kept clean is just two people disagreeing. A fight fought dirty is a thing that has to be repaired afterwards.

Stay on what actually happened this time. Take it somewhere private. If you feel the old material coming up, that is the point to pause rather than continue.