My DH wants to move out because I washed the car I'm the wrong way

No. The first post makes him look like a sulking asshole. The latter posts make him look like an angry sulking asshole. Not a drip feed at all. The context hasn’t changed with the updates.

Also seeing as you’re so fond of the literal, can you explain where it says OP lied about washing the car? She didn’t announce she’d been through a car wash. He didn’t ask. Why does he get to impose the rule? Doesn’t her preference for convenience and a clean car count for anything? Why does that make her a liar?

Im 41, My DH (50) is recently diagnosed autistic. He's always been pretty rigid so the diagnosis didn't come as a surprise.
Yesterday we were going to his parents house me and the kids were driving there but DH was taking bus from work. The car was really muddy so spur of the moment I decided to drive through the car wash on the way there (his parents are quite judgy so I didnt fancy rocking up in a muddy car). Now full transparency DH has asked me not to go through the car wash as it "ruins the paintwork" but he also promised to wash it himself and has only done that twice since we bought the car in March. Anyway we had a nice time with his family and we went out to the local pub for some food DH and his parents had a couple pints and I entertained the kids and drove everyone home afterwards. But when we got into the car my youngest made a remark that we went through the car wash on the way there. DH was totally silent the whole way home (which was awkward as kids and me were chatting away) and went straight to bed without even saying goodnight to me or the kids. Then when I apologised he freaked out saying I don't respect him as he only asked me "one thing" and it shows what I think of him said everyone would be happier if he lived in an apartment alone. I said it sounds like thats what you want. He said yes that's true. So I said " OK fine I won't stand in your way take the car and go get an apartment" to which he then said angrily "you'd like that wouldn't you. This is my home I'm not leaving" like wtf I can't keep up. This morning he's still not speaking to me.

A lie by omission is still a lie

I’m not trying to, I am just unhappy with the misleading thread title and the way the OP has positioned it as her husband being a problem and everyone has decided that he must be controlling or abusive.

He is literally a normal person who has some quirks because of his autism. He is maintaining his boundaries.

They do need to find a better way to communicate, but it would help if the OP didn’t lie to him and wasn’t so dismissive of him.

I’m not trying to, I am just unhappy with the misleading thread title and the way the OP has positioned it as her husband being a problem and everyone has decided that he must be controlling or abusive.

He is literally a normal person who has some quirks because of his autism. He is maintaining his boundaries.

They do need to find a better way to communicate, but it would help if the OP didn’t lie to him and wasn’t so dismissive of him.

If you've suggested marriage counselling and he isn't willing to engage, then really the next step is divorce I'm afraid.

If he wants to keep his car in pristine condition, he needs to be washing and polishing it by hand once a week. If he hasn't washed it for months, he really can't care that much.

None of this is about the car. It’s about control. If it were about the car it would never have escalated to the point where OP had to intervene. It was a test.

An Autism diagnosis isn't a green card to treat people like crap. Yes, people with Autism can be very rigid in their thinking but giving you the silent treatment and sulking, isn't an exclusive Autistic trait, that he can't help. That's an arsehole trait!

My husband won't use mechanised car washes, as yes, over time, they can damage the paintwork, as the brushes etc are very harsh. However, using the mechanised car wash once, isn't going to cause significant damage.

Tell your husband that the silent treatment/sulking isn't acceptable. Next time he needs to chose a date to clean the car by hand, and stick to it, rather than keep putting it off or the car stays dirty. He then can explain to people why the car is filthy.

I'm not sure that's true. I think yes it is about control but it's possible that the need for control is rooted in anxiety- that's fairly common with asd. My BiL (autistic) has lots of things that he feels only he can do because they won't be done "properly" if a third party steps in - and to be fair, when he does something like DIY or decorate it is done to an extremely high standard. However it is also true that he has a lot on his plate and is a champion procrastinator, so, left to his own devices, their house would be falling apart with all these jobs that only he can sort.

In his case the answer has been to put time limits on things (if you don't do x in the next month I will get someone else in to do it) combined with finding some extremely good tradesmen who will work to his (exacting) standards. But my sil loves him and they have the time and the money to do this.