AITA for unplugging my fiancée’s phone (fully charged) to use my own charger when my phone was at 4%?

I (28M) live with my fiancée (25F), and we recently had a disagreement that I’d like some outside opinions on.

We have a USB-C charger that stays in the living room. Technically, it’s mine, but since we live together, we both use it when needed. A few days ago, her phone was plugged into the charger, but it was already at 100%. Meanwhile, my phone was at 4%, and I urgently needed to send an important email (or something similar—I don’t remember exactly, but it was something time-sensitive).

In my rush, I asked her, “Can I use the charger?” while already unplugging her phone to connect mine. She immediately said “No.” This surprised me, as her phone was already fully charged, and mine was about to die. I had already plugged in my phone by then, so I said, “But your battery is full.”

She got really upset, and we had a brief argument about it. We dropped it at the time, but the issue came up again a few days later. She told me that what I did was rude and compared it to her watching TV and me changing the channel without asking. I disagreed, because if she were actively watching something, I wouldn’t just change the channel—this was different.

She insisted that it was “negotiable etiquette,” meaning that it’s still rude even if I think it makes sense. According to her, I should have asked, and if she said no, I should have respected that, even though it was my charger, and her phone was already at 100%.

So, AITA for unplugging her fully charged phone to charge mine in an urgent situation?