Literal thinking?

I want to preface this by saying I don't have autism, but my partner and I think that he is very likely to have it, although not confirmed with a doctor. He scores extremely highly on every autism detection test he's done.

He is a very literal and direct thinker, and I am the complete opposite. I am fickle, I say thoughts without really meaning them, I like to play devil's advocate, I also have a very dry humour. There have been many times in the past where he has taken things I've said as literal, where as for me, I just said something flippantly, it is heavily dependant on context, and I probably didn't even mean it or believe it when I said it. We have had a few confusing discussions in the past, as a hypothetical example, he buys me a vanilla coffee and I don't like it, but he is then confused because one time 5 years ago I mentioned I liked a vanilla coffee. For me I was thinking contextually, maybe I liked the idea of a vanilla coffee, or perhaps I used to like them, or perhaps it was just this particular one. Anyway you get the jist, I probably confuse him all the time.

We had a row today because I am currently ill and he didn't know whether to believe me because apparently one time I said I lie about being ill to get sympathy. I want to stress, I do not pretend to be ill to get sympathy. There was one time in my life where I have had pretend to still be in the pain I was initially in, to get a doctor to actually see me (later diagnosed with endometriosis).

When I pressed him on this conversation, he said he thinks I might have just been trying to defend a girl in a podcast we were listening to. He asked me at the time if what I was saying was true and apparently I told him yes. I have no recollection of this discussion, but I am forgetful, so as much as my brain is screaming that he is gaslighting me, I want to give him the benefit of a doubt here.

I have a feeling that what I said was either greatly taken out of context or I was thinking about this one time I had to "extend" the pain I was in to be seen. He then took that to mean I must lie about being ill all the time. It honestly blew me away that he can think that I'm that much of a narcissist. I think that's what is hurting most. I'm now scared of saying stuff to him in case he thinks something else awful about me. I mean, does he even know me? What else has he taken literally? What ideas does he have about me? I'm really stewing in this.

I would love for feedback on whether this is something which is typical for people with autism? Or is he actually gaslighting me? Do I have to be super careful about things I talk to him about from now on? Have you had similar experiences?