Girlfriend that reacts to emotions

I’m in a relationship with a lovely, caring, thoughtful girl. But we have a recurring issue that I’m really struggle to coach myself around.

We’ve been together for almost 2 years and there’s been a continuous pattern of behaviour where something upsets her (when I don’t follow her manual), she gets really angry / frustrated, and she speaks to me in an unkind way. She will be completely calm and then suddenly react to whatever emotion she’s feeling.

She knows this behaviour isn’t great and she says she’s working on it – but it’s still continuously happening.

I’m trying to coach myself on her outbursts being neutral and not letting them impact the way I feel – but this is where I get stuck. I know I have a manual for how she should be, but I just can’t get to neutral about how she behaves. My body goes into fight or flight mode and I feel ‘victim’ to it.

I’ve also tried setting boundaries, so I do sometimes say ‘Okay you seem quite worked up right now, so let’s talk about this when you’re a bit calmer’ and leave the room.

But I find myself still believing her behaviour is ‘bad’ and that ‘she shouldn’t be acting in this way.’

Then when she’s calmed down, I find myself wanting a grand apology where she’s really ashamed and sorry for how she acted. And if I don’t get one that feels as sincere as I’d have liked, I then don’t feel satisfied.

I know ‘outburst’ isn’t a fact, so if I were to get as factual as possible it would be:

C: Girlfriend says ‘I’m sick of this’, ‘It’s pathetic’, ‘You shouldn’t be doing XYZ’ in a raised tone of voice, before walking out of the room.

A few of my thoughts about it are:
This is unkind
I don’t deserve to be spoken to like that
She’s being mean and unreasonable
She doesn’t love and respect me

F: Upset / hurt

I think what I’m struggling with and what I’d love your help with is the thought – ‘If I coach myself to be okay with the way she acts, then that makes how she acts okay… and I don’t believe it is.’

I don’t know whether I should be coaching myself to be okay with her outbursts or accepting that I’m not okay with them and trying to decide if this is somebody I want to be with.

But I know I’m not ready to make a decision about leaving because I feel so emotionally controlled by her as a C.

Please help!