It’s Never the Right Time
Remember how, when her voice goes shrill, or her eyes get narrow, or her mouth goes pouty, you forget how to ‘just act natural?’ The verb there is ‘act.’
Good acting might just be part of what makes things worse.
Staying put can seem like the right thing to do (especially if your counterpart craves more eye-contact and attention than you do, even on a good day.) However, responding to someone’s upset with apparent calm obviously doesn’t have the desired effect every time.
Plus, it’s perfectly possible that this is more stressful for both of you than either of you realize. Just because you look calm, doesn’t mean you’re not alarmed. And admitting that to her might seem scary, but that’s what I want to make possible.