What should I do!

I have always been into black guys and have tried to be open with my family about it. My family has made some negative comments about it. I started talking to to one of my friends and he’s from Nigeria. After things started to become pretty serious I talked to my family about it. My family is extremely traditional so the fact that I didn’t tell them about my relationship was a big deal. Long story short, and for many reasons I don’t agree with they told me I could not talk to him. They told me that because our cultures are different a relationship would be hard and could end bad. Again, I don’t agree with at all. I am 19 and I knew it was my decision. It’s hard because I want to respect them, but I also want to be able to make my own decisions. We are still dating and my parents don’t know. “Hiding our relationship” is starting to take a toll on the both of us. I’m afraid of the rejection from my family but also don’t want to loose him. I don’t know what to do.