My stepdad is a great and nice guy, and I've suspected for a while that he might be autistic. He's very quiet and reserved, rarely shows strong emotion. Chuckles rather than laughter. He's also fixated on certain things and hobbies, and can talk/ramble about them for quite a long time. He likes puzzles and, what have been given to him, legos. Putting together and taking apart things.
Like I said, no hard evidence, but I could see it.
My wife apparently fully believed I was autistic and thought that I knew I was as well.
I didn't find this out until after we were married.
She would say stuff every once in a while that I took as a poor joke, nothing really mean, just stuff about how I was autistic. That's not her style of humor so I always found it weird but it never bothered me so I would just play along. One time about a year after we got married, known eachother for 9 years at this point, she make one of those "jokes" and I asked her why she why she said that. It led to a very awkward and humorous drive home.
I decided to look into a bit and I can absolutely see why she thought that. Looking back at it now she's always done things to protect me in certain ways and make me comfortable, she always just knew me, better than myself I guess.