Then they're a low value close minded git who you probably don't need to be spending your life with anyway.
Look at it this way. Imagine you were black, but somehow had the ability to change your skin colour (I know this doesn't exist in real life but hypothetically.)
You met a perfect guy... except he wasn't black, and he just didn't want to marry a black person for some reason. Preference maybe, or prejudice.
Now you could go all your life not telling him, and marry him, but you'd be hiding from him who you were. You'd be living a lie. And if you told him and he rejected you? Well... you would want to be with a guy who rejects people based on skin colour why exactly?