I've had interracial relationships, my best love is my son's mother, and she's black...
Unfortunately we got together before I truly grasped Maslow's theory of Self Actualization. In short, I had a lot of growing up (coping, overcoming, developing a healed identity - not being an a**hole, basically) to do.
When two people have dealt with their issues, can carry their baggage and look like refined travelers instead of confused, overburdened refugees - they're able to develop a real bond. An open, caring, respectful love takes two well matured personalities that are compatible.
I didn't deal with my problems in time. But I think it still goes in the 'win' category that we loved each other for many years.
Because of the love I cultivated with her, when I find myself in the arms of a black woman, it's like returning home.
I might carry a torch. One day I'll meet a very savvy, mature, intelligent and brave woman, of any race, who will help me out.
Back to your question. Being objective, two people of different races, getting together in this multi-polar world of news media whipping every side of an argument up into a froth, until everyone has their own "deal breakers" for every friendship, are beating the odds.
It's a cathartic experience to just be you, with someone else who's just being them, seeing the color difference but looking deeper than the skin.
Part of it is the act of two people crossing the color barrier, smashing down old restraining ideas. Another is the difference in culture. There is a different way of life in every family, but differences in race add more factors to the equation.
When you're in a mixed relationship, it's like you sidestep out of the white/black situation, and are two lovers alone on a desert island. Because there's going to be issues on each side. I lost black male friends. She got grief from family members, because I'm the very average white guy. Not everyone got it.
So, yeah, it can last. It takes heart. And it takes maturity. Same as any other relationship. Maybe thicker skin. The ability to bust gang-bangers' and crackers' balls, with equal opportunity to tell them what sh*ts they're being. Without getting shot. That's important. Some people get way too upset over things that don't concern them.