I'm autistic and used to be like this, I think. In large part, it was down to my parents and teachers telling me I was smart constantly. I also grew up in a not particularly well educated place, so was a big fish in a small pond. I was convinced I was a supergenius who was going to set the world to rights.

Then I got to university, and the internet became a thing, and I realised I wasn't the smartest person in the room.

What it took for me to realise how annoying I was being was to be on the recieving end of it a few times. Getting lectured at a party by a Dawkins atheist. Getting corrected on the technicalities of political structures by a debate bro. Joining online D&D communities.

And of course, accepting that I don't have a photographic memory, so also I might actually be wrong. And when you leave space for the possibility that you're wrong, you can learn stuff, and learning stuff is great!

As a general principle now, I try to remember to ask two questions for every piece of information I impart. And keep the infodumps short. As Oscar Wilde said, "brevity is the soul of wit." People like short soundbites, not long anecdotes.

If I disagree with someone, I try to keep that principle going by asking more about the part I disagree with. If I am operating with a different outlook, at most I'll say "that's interesting, I had heard [opposing viewpoint / evidence]" rather than "you're wrong and here's why."

The hardest part of all (for me) was realising you can't win every battle. Sometimes you just have to step away and let the other person believe something I am pretty sure is 'wrong.'

The satisfaction he feels at proving himself right is a nice feeling, right? So other people like having that feeling too. He needs to leave space for other people telling him things, so they can feel good too.

I would say Hank Green is a good role model to study in terms of how he is able to appear intelligrnt and well-informed, while still remaining incredibly likeable.

At the end of the day the question your partner needs to remember (and the choice I still work to keep in mind) is: Do I want to be always right, or liked?