"but it's also the only effective way I've found for myself to calm down and be rational rather than explode and be rash."
Have you told her that? If not, then you should explain to her that it's how you process things and it's not because of her. So she needs to understand that in those cases that you walk away.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.