Traditionally, a wedding marks when a man can first make love to his wife. I'm picturing the opposite. Once the couple are wed, she no longer has sex with her white husband, but rather, exclusively with her black bull. The white husband no longer has sex, period, actually.
And since its bad luck to see the bride before the wedding, the white husband won't be seeing the bride...for at least six months prior. During that time she will be off at a special resort/clinic, getting made over into her bull's perfect woman.