Since there have been a lot of discussions of abuse within Bellamort lately, I will talk about what I do believe in. I do think abuse exists in the relationship, even though I don't fully subscribe to the reading that physical abuse was frequent. I won't say for certain it did not exist, indeed because of Bellatrix's fear in OOTP, but I find it notable that she's never shown or mentioned to be punished despite the magnitude of her mistakes.
Now, where I think abuse does exist, is the psychological aspect of it, and I think it's rather explicit in DLA. My earlier analysis of that chapter shows his motivations and breaks down what's happening in that scene, but something else, which is significant, has only been gestured at in that post.
Look at the sequence as a schedule of reinforcement. She offers devotion ('no higher pleasure'), and he delivers the reward ('that means a great deal, Bellatrix, from you'). Then he introduces the aversive, forcing her to choose between himself and her family, through the mention of Andromeda and Nymphadora and the denigration of her family, the humiliation mounting until she's about to break. Then, at the exact moment when her distress is greatest, he removes it ('Enough') and immediately pairs the relief with elevation, the pruning mission which conveniently aligns exactly with his earlier insecurity regarding her decision to shield the Malfoys from him. It's more a reward for him than her, as it isolates her from her family and binds her even more closely to him, but at least it means she's still in his favour.
The whole scene has a single and coherent intention. It is no escalating improvisation as fandom tends to read it. The humiliation itself is means to an even crueller end, the aversive that destabilises her, breaks her solidarity with the Malfoys, and makes her desperate for his approval again, which he just so happens to hand her.
The punishment and reward are delivered by the same hand in the same minute, so that the relief of the cruelty stopping becomes itself a reward she associates with him. Intermittent reinforcement, affection you can't predict that is withdrawn and restored on his timing, produces far more tenacious attachment than consistent warmth ever could. Her tears of delight and her tears of gratitude bookend the same scene, which is him training the response, and the unpredictability is the point.
This shows her obsession with him is at least partly cultivated by him. Most readings treat her devotion as a given and in part it certainly is, but and this scene reverses the arrow and actively shows him reinforcing it in real time, fuelling it and strengthening it, which means her obsessive love for him is least in part a thing he built, desires, and keeps building, because he needs the supply and he does not want competitors for it.
He is also twenty-five years her senior, as well as her teacher, the one who taught her the Dark Arts himself and gave her all the power she has, making her utterly dependant on him, and on top of that her object of devotion and her commander, with the power of life and death over her and everyone she loves. Every axis of power runs one direction, so I would never frame it as a romance between equals because there is no plane on which they meet as equals. He has age, position, mastery, command, and her own adoration all on his side of the book, and she has only the attachment he has towards her. It is a lopsided bond where the more powerful party manipulates the devotion of the less powerful one and binds her by making her destroy her other ties.
And yet, it exists with the tenderness. The trap of analysing this relationship is wanting to resolve it to one or the other. Either he loved her in a healthy manner (the romantic reading) or he only used her (the cynical one), but this chapter shows an attachment that is genuine and a mechanism which is abusive, and they are the same impulse. He wants her bound to him and because he's incapable of the kind of love that would let her remain free, so the only way he knows to keep her is to feed the obsession so he can keep feeding on it, to narrow her world until he's the only thing in it.
The tenderness is what makes the conditioning effective and the conditioning is what the tenderness amounts to in a man like him.
