My (23F) boyfriend (33M) is acting arrogant and pedantic in front of me and his friends. I find it overwhelming.

My (23F) boyfriend (33M) of three months is highly intelligent. His logic is impressive. He's not only "well-read". He can talk for hours about biology, physics, psychology and art, but he also has an amazing ability to analyze books and movies, and to pick logic errors.
Most of the time I find it amazing because we can talk all night long and I am never bored. We have an amazing chemistry. I understand most of what he says but I must admit that on some specific fields I have much less knowledge. And that's normal. I have better skills than him on other fields (writing skills in our native language, vocabulary, and some other skills).
But I definitely feel impressed by my boyfriend's intelligence, and sometimes I even feel stupid when I compare my knowledge to his knowledge, and his achievements to my achievements. He never makes belittling comments about my intelligence, he even told me that he "our conversations were magical". But I still find it overwhelming, because he has a tendency to talk in an extremely pretentious, pedantic, arrogant and assertive way when the conversation is about his hobbies. And he is too blunt. He admits it. He has this issue with everyone. Me, but also his friends and strangers. Example, he always says "I know what I am talking about", "I am extremely logical".
He also interrups conversations a lot. When I told him to stop, he said sorry, and told me that it was "too interesting to stop talking" and that he didn't want to forget what he wanted to say. He also say to his friends comments that I would consider rude and insensitive like "I am sorry but you clearly don't know what you are talking about" in a condescending tone, instead of "I would have done it in a different way". I love him. He cares about me. He doesn't really want to hurt me.
So why does he act arrogant? I think there are two reasons. First once he admitted that he wanted to impress me. But the main reason is probably his drug use. He has an history of doing a lot of substances, and now he still takes a low dose of stimulants. He never acts in a violent manner but in an arrogant manner, yes. I think he's in denial. He says that drugs make him "intelligent", and that without them he would be a "completely different man" (lazy, unintelligent, exhausted, not confident, depressed and not that interesting). His doctor knows he's taking stimulants but can't do anything since my boyfriend is in denial. He even thinks that I would lose interest without the drugs. Once in front of his ex-girlfriend (we had to bring his belongings) he spoke to me in a very condescending way "Take that box with you" "No, not like that", "If you don't listen to me then..." "But not like that!!!". Maybe that's just me but I would have said "can you please take the box (my name)? " I find his lack of manners humiliating. I don't really know what to do.
TL;DR : My boyfriend is highly intelligent but too assertive and I am starting to doubt my own intelligence.


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