My IQ tests at 155, which puts me in the "highly intelligent" range according to the link given earlier.
My late H had never been tested or diagnosed but clearly had dyslexia, and I would say his IQ probably would have tested around 90-99 once the dyslexia was accounted for.
I fell for him because he was kind, protective and honest. I was coming out of a relationship with a man who was highly intelligent but emotionally cold.
At first things were lovely and although I had to make a conscious effort not to use "big words", after we married the cracks started to show.
As his son got older (5 when I moved in, sole residence) it became apparent that H simply could not cope with any form of interaction with the school and did not value education.
H was expelled from school at 13 and his insecurity about his own lack of academic attainment was a massive, massive problem, which was now impacting massively on DS. Any letter from school was a massive deal and would result in tantrums and threats to remove DS from school and home educate him (turns out his idea of home ed was "we don't have to get up in the morning and he needs at least 6 hours of CBeebies every day including the boring maths and english ones.) H had NEVER once sat down with DS and read to him, with the result that at age 6 DS simply could not read or write.
(DS clearly also has dyslexia but H would never agree to let him be diagnosed. I took over all the education support stuff and things did improve for DS.)
I know OP you've said children wouldn't be an issue with this relationship. However I hope the above illustrates that this kind of gulf between partners can result in problems which have a very hard impact on the relationship (and possibly on others.)
As our relationship worsened, every time we argued I would be accused of "using big words on purpose". When I tried to lower my vocabulary he would then accuse me of being patronising. I could not win (and of course an argument shouldn't be won anyway, it should be resolved.)
The thing that ultimately split us up was not his level of intelligence, it was his level of insecurity in regard to that.
I could have coped with not having deep and meaningful conversations about philosophy, or other forms of music than the BeeGees, or statistical theory - I got that from other people. I couldn't cope with being constantly asked to pretend I wasn't more intelligent than him. And I definitely couldn't cope with watching him undermine DS's efforts at education.
(After we split I maintained contact with DS daily by phone and every school holiday - H moved a few hundred miles to move in with a new GF. After H died I fought long and hard to get DS back to me rather than with his abusive birth mum. Eventually we won through and he has recently passed his functional maths and english level 1. A massive victory considering the way his dad actively sabotaged his education.)