He's still playing games and your son is too immature and inexperienced to see it.
You were NOT all genuinely trying to find somewhere to eat - your 'husband' was taking the piss and trying to make it your fault.
Don't put yourself in situations where he can do that again, ever.
If he tries it again:
'we're not a good family, we're a family in the process of splitting up, because we don't work well together'.
Be prepared too, IF for some reason you do get stuck with him driving you all around, make sure you have a snack in your bag before you set off. Then ignore his games, just brightly say yes to any suggestion, don't make suggestions yourself, just repeatedly give the same response 'happy to go wherever you choose, its your day out', in as genuinely happy and up-beat tone as you can.
No crying. Don't do it. The minute your eyes leak, he can claim you're oversensitive, being dramatic, trying to manipulate, can never be pleased etc etc.
But most of all, just DON'T be trapped into all going out together again. Have other plans 'oh sorry I've booked x for myself, DS can join me if he'd like.' Or just get up and fuck off before he can suggest a thing, ensuring DS knows where you went as well as DP (text both 'Off to x, back by x' )and nothing more.
And fgs, no more cooking, you're NOT his wife any more, you're his estranged wife, you're separating from him, you are not his lackey, chef, or whipping boy any more.