Managing a difficult but important conversation with your partner when this triggers a deep wound in them

Intensity: slightly intense

Closer description: numbness

There is a topic and decision I need to make together with my wife - but we are dancing a bit around it, reason being it somewhat triggers me, and it really triggers her.

Broadly speaking, this decision is how we manage our family finances in a period of life transition. A somewhat unrelated event triggered her to come to me with this conversation again today, but in a state of elevated anger. I feel that what she is asking of us to do is not the most conscious way forward. Today I tried to take a step back from the conversation seeing that she was triggered, mentioning that we should have the talk when we are both in a more grounded state. This only triggered her more, where she accused me of trying to act superior, and not understanding what she is going through. The situation ultimately ended up triggering me a bit as well, I did my best not to react, but a feeling of numbness kicked in ultimately, and rather than holding space I ended up retreating and finding protection within myself.

The conversation on this topic is recurring, and it's a difficult one. It's very triggering, and I feel it doesn't really consciously go anywhere. The most I can say, it that we are making micro-progress after each conversation (but very slow). I struggle to remember when we had a very calm conversation about the topic, where we made real progress, in the last 2-3 months.

Do you have any advice, for how to manage a very important conversation and decision, with your partner or close one, but one that is extremely triggering for one or both parties? Thanks for any advice here.

This felt like an r/Emotional_Healing and r/emotionalneglect topic so I also posted them there.