What 'I'm fine' usually means.

When you ask what's wrong and she says "I'm fine" with the kinetic energy of a coiled spring, you have a choice to make.

You can take it literally, nod, and go back to what you were doing. This is the lawyer's approach to relationships. "She said she was fine, so she's fine." You know exactly what you're doing, and you know it's going to end badly.

Or you can read the subtext. "I'm fine" in this context usually means "I am currently overwhelmed, frustrated, or hurt, and I either don't have the energy to explain it right now, or I'm upset that I have to."

One explicit caveat: sometimes she might actually be fine. You have to read the room.

If she's clearly not fine, don't interrogate her. Don't demand she explain. Say, "Okay. I'm going to be in the living room if you want to talk later," and then actually be in the living room. You're giving her space without abandoning the connection.

Indirect communication is a dialect, not a trap. Learn to hear what's not being said.