My ex for 7 years was definitely smarter than I am -- I was a freshman in college, he was a university professor with a masters degree (we're not from the same university though). A lot of times he made me feel so little about myself, as if wala akong alam gawin and he knows what's best for me. In the relationship he never even consented my decisions, laging sya ang may final say sa halos lahat ng bagay and issues namin. At first it worked to my advantage, because he sort of acted like a parent to me (he's 9 years older), and guided me through college. I am a very opinionated woman by nature, sa school I was quiet but my friends would always consider me a 'leader'. But when it comes to our relationship, I was a different person. I was shy and I had low self esteem. Sabi ko nga sa kanya before, everyone appreciates my opinion except him. He seemed to always negate me, kase sabi nya, "bata lang ako".
Of course I wasn't always "bata". I matured and he didn't see it coming. He hated how I would smart mouth him, he didn't like that I already was sticking to my opinions as I grew older. I started working and I learned more, and he blatantly told me he was afraid kase "lumalaki na ang mundo ko". Gusto nya kase sya lang ang mundo ko, it was sort of an ego boost for him. Until eventually, after 7 years of being together, I finally called it quits. Cliche as it may sound, I wanted to find myself outside of the relationship.
With my current relationship, I can say na same wavelength kami ng partner ko. We think so much alike and we have similar opinions on most things. He's a civil engineer, and I teach, and although technically I have higher educational attainment (I finished my masters degree last year), I learn a lot from him everyday -- engineering stuff, and life stuff. I'd say he learns from me too, kase madalas di ko maitago ang pagiging teacher ko ang hilig ko mag explain ng mga bagay bagay (parang ganito, lol).
Sa couples, one will always be smarter than the other. But if the smarter partner makes you feel bad about not knowing some things, that's probably disrespect already. Maybe the smarter partner dates you to make him/herself feel even smarter, which is very selfish in all sense.