To be fuming that DH has spent the whole day on his laptop?

So if your electricity went down you wouldn't want people to fix it on Christmas day, right? If your bank transactions didn't work, or if your bank was being hacked, that's fine, it's not life or death, Christmas with family is more important, those office workers on call are all massive twats and arseholes.

Another example - Christmas Day 2021, when Santander accidentally deposited £130 million into 75,000 customers’ accounts and then had to rush to try to claw back the money. I’m sure there were multiple disrupted Christmas dinners then too.

https://www.bbc.co.uk/news/business-59826345

What is his job? If he has never worked weekends or late then its utter bollocks. But you know that, or you wouldn't be on here.

What does he do? I could sort of understand this if, say, your DH was a lawyer and needed to prepare life or death court proceedings. But I can't think of much else that is office=based that would be this urgent.

Just one example - data leaks or hacks.

https://www.theguardian.com/technology/2011/dec/25/anonymous-security-thinktank-stratfor

E.g. Christmas Day 2014 - hackers claimed to have stolen the personal details of thousands of clients of the US security think tank Stratfor. I’m sure their senior teams worked throughout Christmas trying to understand the scale of the leak, who had been impacted, trying to reassure clients etc.

(To be clear, I’m not saying this is the case for the OP’s DH, nor that if it were, it would excuse his erratic behaviour and his failure to provide any explanation. Just that it’s not out of the question that a disaster could occur that could lead to senior members of an organisation working through Christmas).

You have my sympathy.
Question : Did you supply him with drinks and snacks ???????????? I know what that's like, it's lonely. I suggest that you install some comfy seats in there and ALL join him as its The Holiday season...we wouldn't want him getting lonesome and start chatting to strangers online.

I would go absolutely ballistic. What on earth could be so important?

OP, how far is this an aberration from his usual behaviour? There's your starting point, you know him better than we do. But no, this is neither usual nor acceptable behaviour, and I'd be digging. I'm sorry you're having to deal with this.

Such as?

Today and tomorrow are holidays and then it’s the weekend so nothing will be happening until Monday

Please tell me you didn’t plate him up a dinner and deliver it to his office? Or did he deign to join you for lunch?

Even people having affairs need to eat. I don’t think that explains why he would miss Christmas dinner. This seems more like a looming personal crisis - be that mental health-related, financial, legal, professional etc.

It doesn’t sound like the behaviour of men I know who have had affairs - they were much sneakier about it. It sounds much more like the sudden, erratic, out of character behaviour of a friend’s now ex-husband shortly before it was discovered that he’d racked up hundreds of thousands of pounds in gambling debt behind her back.

Is he watching porn?

No one in an office I’ve ever met or in my experience of working in one, works on Xmas day. No one would reply to you.

I don’t know OP , Is he in some sort of trouble at work regarding finances or whatever ??, that’s warranting him working since 5 am this morning, still working at this hour , missing dinner & it’s Christmas Day, there’s something going on anyway.

Unplug the computer.

The behaviour just seems far too obvious to be an affair. My friends who have had their long-time partners engage in long-term affairs that they subsequently discovered all report of much sneakier behaviour. I’d wager more that he isn’t as invested in being a foster parent as OP.

Sounds fishy to me! Are you really believing that something could be so urgent that he wouldn’t come in briefly for presents then for dinner? Nope.

Lots of us know what it's like to have an urgent situation at work that can be time consuming. It doesn't explain anything.

What's his mental health usually like? Is he neurodivergent? I still don't think either make his behaviour acceptable but might go some way in explaining it.

I totally agree here.
my dh works for a huge American company and his team deals with 3 different time zones so he often works stupid hours, 8-8 on a good day but can be 8-12 at peak times. It drives me nuts but I know he loves his job and it’s who he is. BUT there’s no way he would work Christmas Day- never in his career has he worked Christmas Day and no one else in his team would. Unless there is a huge issue with cyber security etc.
has he not eaten at all?
if you have young children I’d be seriously thinking about the relationship.
sending a great big hug and support- I get how hard it is x

it does seem implausible that this is a genuine work situation tbh. I wouldn’t be as quick as some to jump to affair but I’d be thinking about his mental health and whether something has happened or whether he’s fucked up at work and is trying to fix it while no-one’s around.

My husband has been on call lots over Christmas. Normally it has been a ‘I’m really sorry, shit has hit the fan I’m going to have to work.’ type situation and it’s normally an hour of emails or calls and some email and phone checking over the course of the day. Whenever it’s happened he’s been quite pissed off and open about what has happened and how he’s trying to sort it.

Oh what ? This has to be a wind up.
Teams meeting on Xmas day ? He's taking you for a mug.
Turn off to WiFi and call a friend round for support.

This.

I'm sorry, whatever the reason for this behaviour. This sounds really hard.

Sorry OP but this is up here with one of the weirdest behaviours I've read on here and I'm 14 years in to mumsnet. I live with my exh for now, and even he manages to communicate like a normal human being if he gets caught up with work

First thing I thought is that he is handling some kind of disaster recovery, and worried sick, but that being so he could have told you.