It's not impossible to find a girlfriend now if you happen to be a white boi, you just have to be able to put your pride aside and adjust to an altered dating landscape.
Of course if you try to posture as an alpha male when women can easily compare you to black men, you'll get blown off. Instead, try transitioning to a secondary, supportive role. Be someone she can talk to and rely on, while expressing interest in her and leaving the ball in her court. There's a niche you can occupy for her that's between a girlfriend and a boyfriend.
She'll most likely still be interested in dating black men and it would be unwise to try to dissuade her from this. More and more women are realizing that they can have great sex with a black man, however they also have emotional and comfort needs. That's where you come in!
I know it may not be exactly what you're hoping for, but a small piece of the pie is better than nothing.