Help me get over this bizarre and hurtful accusation

What other occasional criticism does he offer?

Sounds as though DH should be left to play on his own, jealousy is an ugly thing and to try to show you up in front of a tot has to be stopped now in case it becomes a pattern.

Let’s all laugh or accuse Grandma is not funny, nip it in the bud now, before the GCs get older.

You are over thinking this a laughing rebuff at the time is all that was needed, or some daft remark to the kids like, I knew grandad needed new glasses
You really have blown this out of proportion
Forget it

Thanks, Eloethan, it's helpful to have that put in words.

Just laugh it off.

Hithere, that's an interesting question. Throughout our marriage he's been very supportive, particularly at times of professional stress. And he absolutely does his share of taking care of household stuff (he does the cooking, for example). But, right from the beginning, every so often he would find fault with something I did and rebuke me in a way that would make me feel crushed. I don't want to draw up a litany of examples (I feel a bit bad writing this - he would never do any such thing. That's partly out of a rather admirable reserve and discretion, and partly because he generally doesn't see the point of talking things through, and certainly not to srangers. Whreas I've found the responses here really thoughtful and helpful.) So I'll just give one example. When our newly-acquired cat was still being kept indoors for the period required by the Cats Protection League, we had a litter tray in the conservatory, which adjoins the dining room. We had invited some people round to lunch, and were a little concerned for obvious reasons. So I said 'I'll get the second litter tray ready and put it just outside the back door, and if the worst happens, I'll do a quick swap'. His response was 'No. I don't want histrionics.' I was really taken aback - I thought I'd made a practical suggestion, and I am fairly sure (unless I delude myself) that no-one would describe me as histrionic or hysterical. But it felt like a criticism that went way beyond the actual thing that had occasioned it. And it wasn't easy just to find a quick riposte.

I wonder if he used the wrong word about the litter tray, and meant to say he didn't want a fuss over changing trays.
My response, in any case, would have been "There's no histrionics involved." with a look conveying "You must be nuts." Then carry on and do it.
My reaction would come from not accepting what he said as sensible and also not believing that any sort of 'rebuke' should be being made.

His non-explanation re the cards is strange. My reaction again would be The Look and "I definitely wasn't cheating."

Try to choose not to feel 'crushed' but instead to feel 'he's being totally unreasonable with that'.

Using the word histrionics about the simple, straightforward, and eminently sensible idea of swapping a used cat litter tray for a clean one suggest inordinate anxiety to me. An equivalent response, by which I mean one that dealt with the crushingness, might have been: "Don't be rididculous."

In short, practical solutions are not histrionics.

Just don't tell him about ideas like that in future. Simply do what you think is a good idea without saying anything.

If he is someone who is anxious about trivia, maybe his anxiety levels were up while playing a game with a three year old – it can be stressful ?.

So I'd say, don't feel crushed by someone else's social anxiety. Do no harm and take no shit. Good luck. ✊

Very much overthought.

FarNorth and Baggs, these are great responses and I take them on board. I also appreciate the more bracing reactions from some people who would never let these things get to them. Gransnet is a great institution!