"You Always Take Their Side": When Fairness Feels Like Betrayal in a Reasonable Voice

You told them about the fight with your mother, and instead of siding with you they said "well, I can see her point." Something locked shut. Because you did not want a mediator. You wanted a teammate.
One of you approaches conflict like a judge. Both sides deserve a hearing, fairness means objectivity, and telling you that you might be wrong is a form of respect. They think they are helping you see the full picture. The other approaches conflict like a war. You came home hurt and you needed your person standing next to you, not across from you, and "I see their point" does not sound fair. It sounds like betrayal in a reasonable voice.
This runs along the Cooperation facet of Agreeableness and how it gets pointed. The judge weighs the situation on its merits even when it is their partner venting, because to them loyalty without honesty is a kind of collusion. The teammate reads that same weighing as abandonment, because to them honesty without loyalty is being left alone in the exact moment they needed backup. The maddening part is that both are right, which is what makes it feel unsolvable.
The fix is answering the right question. Before weighing in, the judge can ask "do you want me to help you think, or do you want me on your side right now," because those are two different jobs and doing the wrong one feels like betrayal. The teammate can learn to name which they need instead of assuming. They are not against you and you are not unreasonable. One of you was built to weigh and the other to fight, and you have been answering different questions with the same conversation.
You can see where each of you lands on Agreeableness and its loyalty facets with the 30-facet OCEAN personality test. It takes about 15 minutes, the domain scores are free, and a compatibility report shows whether "you always take their side" is a loyalty problem or two people wired to answer support and fairness in the opposite order.