Rodolphus had never been particularly suited to his wife. It had been a marriage made of convenience, and mostly negotiated by their parents. He'd been happy enough at the time; she'd had an ethereal beauty all of her own, and she at least had backbone and aspirations (unlike Narcissa).
It was not their personalities that met with conflict, however.
He could still remember their honeymoon like it was yesterday. He'd been nervous of doing something wrong, and terrified that neither of them would enjoy it. To this day, he's not sure whether it had been normal for newly-weds to feel like that, or if it had in-fact been a premonition.
He'd gotten hard, alright; he'd been aching from the moment she'd taken her clothes off. She'd spread her legs and laid back, telling him to go right ahead.
But he hadn't wanted to hurt her. His brother, already married, had told him how to see to a woman properly. "She'll like it gentle," Rabastan had said. "You got to prepare her right, otherwise it'll hurt. Don't be too rough, or she won't want to do it again."
So he'd taken his time, and lavished caresses and kisses over every patch of bare skin he could find.
She laid there like a block of wood, barely responding to anything he did. It had been off-putting, to say the least, and he'd honestly had more pleasurable sessions alone. With a marathon effort, he managed to spill his seed inside her before softening almost instantly.
She didn't come that night. Or the next. Or the next. Eventually Rodolphus gave up trying to pleasure her.
Then he came, and everything changed. Rodolphus was a good pure-blood. His brother had already joined their ranks, and it didn't take much convincing before Rabastan had convinced him to sign up too.
When he asked Bellatrix if she'd like to become a Death Eater with him, he didn't expect the level of her enthusiasm.
Two years on, he walks into the Dark Lord's headquarters to find his wife bent over a table with the Dark Lord ramming into her repetitively. As Rodolphus watches, he lifts his hand and brings it down with a resounding smack onto her bare skin.
That's not what has him transfixed, however. What glues his feet to the floor is the sight of Bellatrix screaming not in pain but in pleasure, as he twists her nipples sharply and her limbs thud against the hard wood of the table.
As Rodolphus watches, Voldemort looks up and smiles at him.
"Let's try something new, tonight," Rodolphus says to Bellatrix the next evening.
She looks startled. "What, in bed?" she asks, a sneer in her voice. Her surprise is not unwarranted; they were no longer even having sex, outside of their obligatory once-a-month coitus in their vain attempts to produce a child.
"Yes," Rodolphus says.
"What do you want to do?" she says suspiciously.
"I want to see how hard I can fuck you before it gets too much for you," he says. The phrasing was deliberate; very deliberate indeed.
As he expected, her eyes narrows at what she perceives to be a challenge. "Alright then," she snaps.
Rodolphus isn't good at rough sex. He likes to take his time, to caress and feel. He finds it difficult to remain hard as he pushes his wife violently against the wall and thrusts forcefully into her.
Only the sight of her moaning and squirming in pleasure stops him from asking her if she's still okay with this.
And as he yanks her hair so hard that he can see neck straining as her head is pulled, her body shudders and her walls contract around his cock as she orgasms.
That night, it's Rodolphus who's left unsatisfied.
But the next night, he makes the same offer. And the night after that, and the night after that. Because satisfying his wife might not keep her out of the Dark Lord's bed, but at least it'll keep her in his.