If your partner is sharing something important to them, they are going to want you to listen/respond in one of two very very different ways:
The “Be” Mode: where your job is to be as emotionally bonded, and present, and caught up being the “audience” to their story they’re telling you. During and at the end, if you’ve been doing this right, they will feel you totally on the roller coast ride with them, dizzy with all the feelings and nuances of this way and that. “Right with you” are the watchwords. Interest. Presence. Caught up in the story. Nothing else required.
Or, they could want you to be in the very opposite, “Do” Mode:
where it is your job NOT to get caught up in their story, to listen yes, but with some detachment, distance, holding yourself back, question their decisions, suggest alternatives, push back, feedback, critique, do NOT get caught up in what they did, but instead offer up different routes, other options. Help them out here. They want you to think through where they went and fix the situation. If you just sit there with a dumb-founded totally caught up in their situation look on your face, they’re likely to be pretty pissed, and feel like they’ve wasted their breath, or worse.