Black Soul, White Heart by Hailey Edwards

Vonda Winterbourne is, sadly, a lady. Much to her regret. And her parents expect her to act like one. That includes marrying a nice white witch who can provide her safety, companionship, and all the comforts one could desire in their gilded cage.

Hiram Nádasdy is no gentleman. He’s a black witch with a reputation that strikes terror in the hearts of his enemies. But not in the girl. No, the girl is fearless, reckless, and determined to know him. He ought to reveal the darkness lurking in his heart and scare her away before it’s too late, but he’s curious about her as well. And, frankly, he’s not sure it would work.

Black witches don’t befriend white witches, and white witches don’t fall in love with black witches. They certainly don’t marry them.
Or do they?