Parents won't accept my SO :(

How do I accept that my parents will never be happy with who I'm with?
I've only ever brought home one boyfriend, and they made my life (and his) a living nightmare. He wasn't "good enough" as he was of a different race and wasn't as educated (they want me to be with someone in the professional field) It wasn't enough that he made me happy. To them, he was a loser and they put just enough pressure on us that it finally worked and we broke up (other factors came into play as well). Many of my friends say that the things that went on in my family during the time I was with my ex came very close to what many consider to be emotional abuse.
Fast forward a few years and I'm in a new relationship. One that is becoming very serious. This might sound silly to most of you here, but I've been so terrified of the same thing happening, that they don't even know he exists. He is a different race, 4 years younger, comes from a working class family, and although he is in school with awesome career prospects, I know that's not enough because by their standards, he should already be set and making a decent salary. 
I'm tired of living in the shadows. I want to be open with my relationship and have the freedom to be with whoever I want without there being such awful consequences. My little brother is also dating a girl of another race but he is able to be open and doesn't get the same treatment because "he is the boy and so the pressure to be successful lies on him" so basically it doesn't matter what sort of girl he brings home because he is going to be the one to provide.
But guys, shouldn't  it be enough that I'm an adult and that he treats their daughter like a queen? Good men and few and far between. Am I really supposed to let this one go because he falls short of THEIR standards?
Has anyone gone through anything similar? Yes I realize this is not the norm, obviously if I'm a grown woman who is afraid of her parents, I've been through years of conditioning. Also take into account we are from another country/culture.
Also, even though they haven't met him, there is no doubt they will be unimpressed with my guy for the reasons stated above.