I can't believe nobody's thought to question what kind of things the O.P is saying to be misunderstood by people of working class background? What topics are you discussing? Do they even have anything to do with your University degree? In order to [hopefully] make a correct judgement on the situation... it's of pretty significant importance!
I mean, the level of one's intelligence
can have very minimal to do with one's level of wisdom! When I think of a typical University student, I don't think of someone of superior judgement... I think of someone who is
learning to be educated in one specific field. One specific field in a world of countless opportunities!!!
Certainly, if that's all they have under their belt, they'll get no praise for their intelligence from me. WoopDeDoo! Srsly! However, if they can also apply wisdom [read: comparatively advanced common sense; a quality everyone thinks they have, but few do] then I may consider them 'bright' and depending on the person perhaps 'gifted'... and THAT is when I'd consider them of noteworthy intelligence. Otherwise, they're probably just average! Average is common! Many average people go to University!
Whilst a University student should have a higher aptitude in their area of expertise [although there's no guarantee's

]... with anything else they tend to know as little as the rest of the world. Important point: Most people know very little!
Therefore, it's impossible to make a judgement over whether you, Nihilist, are actually speaking sense to these people of an IQ too low to understand - or whether you do just come out with some tripe! It's my understanding that regardless of social class, on a superficial social level, people respect intelligence. Obviously, if the relationship or involvement in discussed topic is deeper [as is the case with your partnership] problems may arise! People of differing intellect have trouble understanding each other, this is true and has been proven! However, it's important to be honest with yourself over whether this is indeed the case.
Obviously you thought your partner was smart enough to date! Do you consider him your intellectual equal? I actually got the impression from your post that you think he's intelligent, but also the rebellious type who rebels against social standards/ expectations. If this is the case, then it's just as possible that you're naive to his points of view! This would explain why he's reluctant to praise you for your education, and actually confirms his personally held theories on the stupidity of it all.
Basically, it's impossible for anyone to on this board to know the truth of it all. The best we can do is assume that you're incompatible together! I, however, don't assume that this is neither his fault nor your fault from the information that's been provided. There's too many possibilities that have remained untouched for that.