As the others said, it is a no go but not because we're "bigots" or whatever, it's because of the mixing of energies during the act of sex that we frown upon interracial sex.
Energies from different races aren't really compatible to that level and can bring no good to the people involved in it, especially if we're talking not only interracial sex but interracial conception of children who will be born of mixed race, the race is hardcoded in a Soul, the most advanced Souls are then hardcoded to be of certain races, mixing them up makes it harder for more Ancient Souls to reincarnate and there are other problems of this sort.
I feel this was needed to be explained.
Also, I want to clarify: it's harmful to BOTH people involved in interracial sex, regardless of their race.
The typical case you see around is a white woman with a black/brown man, and as we're mostly white we could think that only the white woman is harmed by this, but this harms the black/brown man too.
Not that there haven't been somewhat "successful" interracial couples, but it really makes no sense to pursue something like that, and with a certain level of spiritual awareness you'd most likely never feel seriously attracted to someone who isn't of your race. You could acknowledge that a man/woman is objectively beautiful even if they're of another race, but you wouldn't feel the sexual drive nor "fall in love".