On a mundane, non-spiritual level I dont date women who have been with blacks. Once they become wrapped up in nigger shenanigans it's really hard to break from it, ask yourself this: what kind of music does she like? What does her social media look like? Does she like to go off to parties, bars, etc? Does she smoke a lot of weed and drink a lot? It might be worthwhile to simply find a a new girl. Lotta fish in the sea champ. I hate to say this but unless you get a swastika neck tattoo and she knows from day 1 what you are, you have to make a verbal stand against this behavior from the women in your life.
Race mixing in general is spiritually degenerative on a minor level, but the cultural/mundane aspects of white women who fuck niggers makes them the worst kind of race mixer. For example, an asian woman dating an indian guy, will result in mixed, spiritually degraded children but only slightly. The Jews use white fem/black male relationships to propagandize against our race, to sexually degrade us in pornography and subliminally influence us in advertising, netflix shows, and so on.