To have walked out of the restaurant

i.dont get why husband couldn't help

They are 5 and 3, you are their parent, try parenting them

Presumably he did once she walked away.
She did say all the adults were trying to stop the children fighting.

As my kids are only young, maybe I'll change my mind on this, but if my kids have kids and in a few decades we're out at a meal, I probably wouldn't discipline them/step in if my son/daughter and their partner were there. Not short of an emergency.
OP, I would have taken one out, and got dad to take the other out, and say I want to see x/y/z from you, or we're not eating out. And get GPs to order. If their behaviour didn't improve, GP could get yours put in take-out boxes. This way, you don't have to feel frazzled/worried about others.

I don’t see a problem, I would’ve done the same, and probably have done over the years. My two, now 21 and 17, used to bicker and play up constantly when we ate out (and pretty much all the time). Sometimes as a parent you have to remove yourself from the situation for a few moments so you can regain your composure and deal with them. You left them with other adults. Don’t worry about it.

Next time just remove the food, pick one of the kids up, physically, and plonk it next to one of the other adults, tell dad to pull his finger out and sort his children. Take a deep breath and scream 😱..joking.

I did this many many years ago in a supermarket my sons were 5 & 6 and they did not stop bickering pushing each other tripping each other up .. I had come to the end of my tether left the trolley and walked out they ran after me and new they had gone to far.
If you needed to step out for a few minutes and another adult was there that's all good its better than losing your temper in front of them .. youre so not unreasonable but all the perfect mummy's on here will say its absolutely terrible because they're perfect parents ..stop being hard on yourself you're only human x

You reached the end of your tether and took some space. You left your children, with their their parent and their grandparents. No you didn’t do anything wrong.

But it does sound like you’re struggling. Maybe you’ve had a difficult day, or maybe you’re finding motherhood overall quite hard, and that’s ok. But have you got any support or anyone to speak to?

I adore my children, but I found eating out with them exceptionally draining until they were all over 5, and even now, with them being between 13 and 7, sometimes I want to walk out and leave them with their dad because, yes, they still squabble. We can adore our children but also find them difficult. Parenthood isn’t easy.