AIBU to be upset after he turned off my work laptop?

If you're talking about updates to a laptop - honestly how long and frequent can they actually be? If the updates affect your work, then complain to work.

I WFH. My other half knows, without me even having to say, that my work laptop is off limits. We get updates where we’re asked to leave the laptop on overnight so stuff can be rolled out so on the odd occasion I’ve done this and if he switched it off I’d be cross.
His comment about divorce is really extreme. Does he usually threaten you with divorce when you challenge something he’s done? (Although I suppose it depends how you challenged him and what you mean when you said you went mad).

I would never turn off my DHs work computer, or touch anything to do with work. His office set up is none of my business. If he left it switched on overnight I would assume that he had done so for a reason.

And to threaten divorce over it rather than just apologise?

As someone upthread said, take him at his word.

Is this the tip of a very unpleasant iceberg?

This.

Does your course eventually make you better qualified than him OP?
I had similar with my ex, he never wanted me to progress, get any qualifications etc

Give him his divorce with a speed that will make him dizzy.

Errr, come on op, there is waaaay more going on here than a laptop. Sounds like you need a lawyer.

I'll be honest, I'm baffled. You're more upset that he shut your laptop than him telling you he wants a divorce?

i would not touch someone else's work laptop.
sounds like he is resentful of OPs job.

Don't assume.
Ask.

It's not her responsibility to tell an idiot man child not to touch a work computer he has no idea about. That's a given.

It's his responsibility to leave it alone or ask first.

You do leave it on if it is running something. My husband works in IT, his laptop frequently is left running when he is testing things. I’d shut it down on pain of death.

You wouldn't say
"Hey, did you mean to leave this on. Will I close it down for you?"

Like a reason able person?

No he didn’t. You don’t shut down someone else’s computer “as a favour”.

It's not normal to shut a lap top with out checking with laptop owner first.

You shouldn't be leaving your laptop on all the time. He shouldn't be randomly turning it off.

What's actually going on in this relationship?

No.

It's not normal.

You dont touch other people's electronics unless asked. ESPECIALLY work ones!

You have more than a laptop problem. Do you even like each other at this point?

But for future reference if the work is really important you really should be saving and backing up these documents regularly. Goes for any kind of documents/photos really that mean anything to you.

Save any important links as bookmarks or quick access tabs on your laptop so they're easy enough to access for next time. You can also schedule PC updates.

Does he often threaten divorce and that’s why you’ve completely ignored that aspect of the conversation?!
I think you may have bigger problems than the closing of the laptop, which is frustrating. Isn’t there an option of saving it as you go rather then leaving it on overnight?
If you’re with someone who threatens divorce over seemingly minor things then I wouldn’t be hanging around, if you’re more bothered about the work then the thought of divorce I’m not sure the relationship is working for either of you

everything else aside, it’s not about saving stuff. I completely get it. I have lots of links and pages open and before you say you can favourite them, no they are sites that require log ins and even if they laptop locks (which it will) those pages remain when I log back in. Also certain spreadsheets which may be needed would be ready and open.
I understand the stress OP.

You need to learn how to use your laptop, or get a MacBook which don't push the relentless updates that windows ones do. That said, he shouldn't have turned it off. That's insane. I would never touch anyone else's computer and if anyone touched mine, I'd be furious. It's often doing things that can't be seen.

This doesn’t make sense to me. How is getting an update going to stop you getting entry to a Zoom and then make you fail your entire course? If the laptop is shut down, the update wont happen, and then when you turn the machine on , there will be a prompt to ask if you want to update now or later. And you could get admittance to the Zoom late, or get a recording .. And surely you save your work as a matter of course, even if you are only walking away for a few minutes..
It sounds like a major overreaction on your part.
Obviously it’s better for him not to touch your laptop, but sounds like you are making a major deal over something that is just a bit annoying. There’s obviously other stuff going on here, this sounds like last straw issue , possibly for both of you. What else is happening, OP? Do you want to talk about it? Do you think he did it on purpose to upset you, is it part of a series of actions to undrermine you?

Online proctored exams are strict - I did one recently where I had to log in 30 mins before so I could join the queue to have the room/desk/computer checked out before I was allowed into the exam (I had already done a pre-exam check on the laptop and shut down everything but the exam software). I had to show the proctor the (empty - no uncovered windows/whiteboards/posters/other people) room and empty desk or they wouldn't have let me take the exam.

I'd logged in the required 30 mins early, and got into the exam exactly on time - an update at the wrong moment could absolutely have scuppered me (and my IT support is on the other side of the world - they have been known to schedule updates in the middle of the night their time, forgetting that for some of us that's the middle of the afternoon)

So it's not farfetched at all...

Mind you, I have a mac, so shutting the lid would have been fine.