Bellatrix Black is one of the most powerful witches of her time and the most cruel and fanatic servant of Voldemort.
She has one son, Lesath Lestrange, with Rabastan Lestrange (canon), but she never was in a relationship with the latter. Bellatrix Black has unconditional love for Voldemort who does not love her. Instead he uses her and lets other Death Eaters — such as Rabastan and Rodolphus Lestrange — abuse her sexually and otherwise.
After the war, Bellatrix Black is sentenced to life imprisonment in Azkaban.