She goes and goes and goes and goes until you can see the volcano bubbling underneath and it's about to burst. I know the pattern and I've seen it a ton of times. She'll even start sending warning signals..."I need a break.." etc, and I'm the type where if she says that I whole heartedly encourage her to take one, but taking the step to actually do it is like a gigantic mental barrier for her.
I'll beg her to take a break. Take a night out by yourself, go hangout with...whoever. There's actually been times where I've had to take the initiative setting it up for her because she doesn't, and basically almost force her to go out and get away for a few hours. It's led to some of our most heated arguments.
And every single time afterwards when she gets back she always seem to feels better.
Lather, rinse, repeat. I love my HCBW immensely but it takes moving heaven and earth to get her to take time for herself.