Rodolphus Lestrange regretted following his father's wishes in joining the Death Eaters more and more as each day passed. He had not even been committed to the cause for a full year and he was already questioning what he'd done. It wasn't for reasons related to the message or the cause, those were beliefs he had agreed with and supported since he was a child. It wasn't the work, which was gruelling and messy and risky. He actually enjoyed that part, found it cathartic even. He was becoming angrier and angrier as the days went by and was thankful for the outlet. No, he regretted his choice every day because of what it had done to his wife.
It was slow to start with, the way their new escapades took her over. Anyone in the know would have just thought her enthusiastic about their new adventures. She trained hard, harder than any of the other recent recruits, but Rodolphus had always known she was competitive. She put hours and hours into learning combat skills and strengthening her magic, spent days on end shut up in their training room at home, the blasts vibrating though the walls the only sign of her presence in the mansion. This was unsurprising. She had to be the best, and she was, a fact that did not go unnoticed by their new leader.
This was the source of Rodolphus' first regret. Ever since they joined, Bellatrix had become so drawn in by the Dark Lord's power and charisma that it often made him question if she had feelings for him. Whenever they would have meeting she would sit at the Dark Lord's side, completely forgetting that her husband was right there too. She hung on every word he said, completely enraptured, and Rodolphus wasn't the only one to notice. He heard the others whispering about it, about how she was making a mockery of him right in front of everyone. It made his blood boil just to see them together.
Everything except the Dark Lord and the cause had disappeared from her priorities, himself included. He couldn't remember the last time they spent actual time together that wasn't their obligatory monthly visits to see her parents. Even when they were there, all Bellatrix could talk about was him, and the progress that the cause was making, encouraged by her parents enthusiasm. She was beginning to sound like an old gramophone record that had been scratched so badly that it only played one song verse.
His second regret, with regards to how joining the Death Eaters had changed Bellatrix, was how it had brought out a hideously ugly side of her personality. The charming, fun loving, arrogant but funny woman Rodolphus had fallen in love with was gone, and had been replaced by a cruel, cold and violent maniac. Bellatrix had become a tyrant, whose only joys were inflicting pain on others and using her impressive skills as a justification to act superior to all except the Dark Lord. Rodolphus didn't recognize her anymore.
Growing up, Bellatrix had never hidden the fact that she had a mean streak, or that she had certainly inherited the infamous Black temper, but this was something else entirely. Once upon a time, Rodolphus had found her dark side amusing, had encouraged and enabled her, even joined in, but now she was nothing more than a ticking time bomb. The others had started to distance themselves from her after she slashed the chest of one of their fellow Death eaters during a meeting for questioning her, with a knife he didn't even know she was carrying. When he'd asked her where she'd got it, she refused to answer and sent him across the room with a stunning spell.
This wasn't just anger, it was sick. While they were out on mission, Rodolphus preferred a swift kill. Clean, quiet, simple, but Bellatrix liked to torture whichever poor muggles they were dispatching of that night for hours. He looked on disgusted at the glee in her eyes as she watched their screaming, sometimes bloody bodies dance on the floor in pain, waiting until they were literally begging for death before delivering. Anyone who dared try and stop her got incapacitated, Rodolphus had learned that the hard way.
He'd never seen anything so twisted in his entire life, she seemed almost aroused by inflicting unnecessarily cruel pain. This newfound joy of causing pain had even made its way into their bedroom, on the increasingly rare occasions when she did go near him, anyway. The first time it had happened since this sadistic streak had bloomed, she had some stranger's blood not even dry on her hands. It had made Rodolphus feel sick as he scrubbed it off himself in the bath.
Rodolphus was losing her to it, and he had no idea what to do. He missed the woman who liked to sit in silence and split a bottle of wine with him, the one who was always reading something because she always longed for more adventure than this life could possibly give her. Just when he thought he'd got his wife back, after the shell she morphed into after her sister betrayed them, she became something far, far worse.
It was eating him, the constant cycle of anger, disgust and loss. It was a weight chained to him that he dragged around every day. He tried to get rid of it, tried to make Bellatrix see sense, see the truth in how she was acting, but she didn't care about anything he had to say anymore, not unless it was related to the cause or the Dark Lord himself. He refused to accept that there was nothing to be done, that the monster who had replaced his wife wasn't permanent, but a part of him knew it was. You don't fall down a hole that deep and just emerge from it like nothing had ever happened, but Rodolphus still wanted to hope.
Of course he still loved her, which was half of the reason he was so angry all the time. He knew who she was, who she used to be, and it certainly wasn't this. He wanted that person back, the cocky girl who was never wrong that he met in first year. The young woman who told everyone she was stronger than everything, but displayed her vulnerabilities in her eyes. When he'd thought of them as partners in crime as they grew up together, he hadn't imagined that it would descend into actual crime, and that skill and power would go so far to her head that she would forget him completely.
He felt so weak, completely powerless. He was outraged by what she'd become, but he clung hopelessly to any sliver of her old self. They'd both found that they still worked very well as combat partners, and she would sometimes suggest that they duel together at home for practice. She seemed like her old self then, wasn't ignoring or insulting him. They felt like themselves again, and those exchanges had often been positive, but if he used the rare moment of calm to challenge her behaviour then everything fell apart again. He'd learned that following along with her wills generated the best behaviour from her, but he was far too angry about everything else to savour the moment. He ended up regretting it every time.
He'd learned to keep out of her way after she had outbursts or he found her arrogance too infuriating to suffer. He was getting far too close to losing his temper with her and hurting her. As much as he didn't want to do that, he felt she needed it. Her egotism was getting too strong, but he didn't want to be the one to have to do it. He just wanted the woman he'd fallen in love with back. She was unrecognizable now, and it seemed that there was nothing he could do to change it.