Most arguments are two people answering different questions. Agree on the question first.

Many arguments are two people confidently answering two different questions and assuming the other is being unreasonable. One of you is discussing whether it was fair, the other whether it was allowed. Both can be right at once, which is why the volume keeps climbing with nothing getting resolved.

Next time it starts going in circles, stop and ask what you are actually deciding. Say the question out loud and get agreement on it before either of you says another word about the answer. Half the time the disagreement disappears there.