Disclaimer: The characters here and the world they inhabit are the creation and property of JK Rowling and her assigns.
Nymphadora had always known it wasn't a perfect marriage. Mum was just a little too quick to smile and nod when Dad had a business trip, and the smile didn't go all the way to her eyes. Most families had mums and dads who came home every night. Nymphadora knew that lots of parents occasionally had to be away from home, but this seemed a little deeper, as if Dad couldn't stand to be home with Mum for very long. Dad was wonderful, though, so the problem must have been Mum.
There'd been a battle when she'd gone to Hogwarts. Dad wanted her to go to a "normal school, away from wizarding wars and crazy pure bloods," but Mum had prevailed. In exchange, however, Nymphadora spent her summers with Dad's family. "It's better this way," Dad had explained. "You'll get to know both sides, and not just your mum's stuffy attitudes."
Nymphadora had a glorious time. Hogwarts was the best place to be in the world, except when she visited Aunt Sue, Uncle Tim, and their kids. She had the opportunity to go play on playgrounds, ride bikes, and go camping. It got uncomfortable when Little Tim and Bitsy started calling her "Nymph" and laughing, but Dad quickly fixed that by saying that she should be called "Tonks" from now on. Nymphadora liked it. It was far better than some stuffy pure blood name.
Sure, Mum was good for learning nifty spells for getting spaghetti sauce out of one's best jeans, and she was the only one Nymphadora wanted when she was sick. Yet, for everything else, Dad was a far better pal, and he taught her how to get into mischief and still make Mum laugh that sad little laugh. Dad was much easier to be with.
It did seem a bit strange that Mum and Dad had separate bedrooms. "That's because I'm always coming home from my trips at strange hours, and it's better not to disturb the wife," he said when she asked about it. It made perfect sense, but as far as she knew, mums and dads slept in the same room. Uncle Tim and Aunt Sue did, and most of the mums and dads on their TV did, too, so Nymphadora knew it wasn't a Muggle thing.
Nymphadora knew it couldn't be a pure blood thing. Sometimes she'd peek out her door at night when her parents came upstairs. She saw the way mum would look at dad when she reached her bedroom, and then how mum's face would fall when dad walked past and into his own bedroom. Somehow Nymphadora knew that two bedrooms was entirely Dad's choice.
She could put such questions out of her mind at Hogwarts. As she grew older and boys became more interesting, Nymphadora decided that her best mate was her perfect mate in every way. Besides being absolutely adorable, Charlie was aces at flying a broom, and he was brilliant at coming up with a nifty plan and helping to carry it out.
They started spending more time alone during seventh year. Charlie's kisses were amazing, and she thrilled at the thought of what would come next. The only problem was that sometimes he asked her to look like other girls. The day they nearly went too far, she had morphed into that snotty blonde Slytherin in their Defense class, which for some reason made Charlie more amorous than ever. After thinking about it, Nymphadora cooled things off a bit, telling Charlie that she wanted to wait until they could be someplace nicer than a broom closet or abandoned hallway.
She stayed home that summer, because Auror training would start less than a month after school ended. That was when Nymphadora realized exactly why Mum was always so sad. It started at dinner on the nights Dad was home, during which Dad spent the entire meal poking fun at the pure blooded witches and wizards he interacted with at the ministry. He had a way of making it sound as though every single one of those laughable souls was actually Mum. Mum would shrug or shake her head at the appropriate points in the conversation, and then quietly send the dishes to the kitchen, where she would follow them.
In the evenings, Mum would work on knitting or sewing while Dad turned on the wireless and sat with a drink. When it was time to go up to bed, the same routine would play out that Nymphadora had seen several times before. Mum would stand near her door, looking inviting and hopeful, while Dad went on to his bedroom. Then Mum would sort of shrink and gently shut herself into her room.
Most nights however, it was just Nymphadora and Mum. Mum was a lot more jolly when it was the two of them, listening to stories of Auror training with shining eyes and speaking words of encouragement at just the right times. Afterwards, they would clear up the table and wash the dishes together. Mum seemed interested in the Muggle ways of doing those things, but spent time teaching Nymphadora the proper spells, anyway.
Then Dad would come home, unless he was on a business trip, and Nymphadora finally realized how strange it was that he always smelled like flowers. One night she caught a glimpse of Mum's face at just the right moment-hurt, rage, sadness-before Mum had a chance to switch back to that placid look she usually wore.
Finally, Nymphadora had to ask. "Mum, he cheats on you, doesn't he?"
Mum shrugged and looked away. "He was never as interested as I thought he was. We got caught up in the romance of how he saved me from my family. By the time I realized that he was... the way he is... well, you were growing inside me."
"Have you ever done anything?" It didn't seem possible, but fair is fair.
"Of course not! I'm a married woman!"
"He's married, too."
Mum shook her head and shrugged, just as she often did with Dad at dinner. "But I'm fond of him, and I don't want to hurt him. Besides, there's no one who wants me."
Over the next few years, Nymphadora realized that wasn't quite true. Mum didn't do much besides work at the hospital and take care of the house, but once or twice Nymphadora intercepted a glance that went a little longer than strictly necessary, and then Mum would break eye contact with a very red face. Mum's admirer was an odd choice, and certainly not whom Nymphadora would have chosen, but she was discovering that there's no accounting for what the heart wants. Besides, in the handful of interactions she witnessed, this wizard was so gentle and caring toward Mum... Well, Nymphadora did not want that wizard, but she wouldn't mind a wizard who treated her like that.
She let Charlie go without a backwards glance. He was a little too interested in other witches, and Nymphadora was quickly realizing that was too much like Ted Tonks for her taste. From time to time, she wondered if he'd found a witch who could morph, and whether he ever asked his new love to look like Nymphadora Tonks. After a couple of years, it didn't matter. She found herself face to face with someone new.
He really wasn't new, he was quite old, not that much younger than Mum, actually. But he was smart, and sweet, and so kind to help Nymphadora whenever she dropped something or tipped something over. That seemed to happen all the time, now, but one couldn't worry about bumping into things or tipping other things over when he was around. Best of all, he called her "Dora." She'd started to chafe under the name "Tonks," and it was nice to have a special name, used by the most special wizard she'd ever met.
The wizarding war intensified, and yet Dora couldn't be entirely sad. She achieved her heart's greatest desire, and although things went from bad to worse in the wizarding world, she couldn't quite mourn. She was in love and it made everything a bit less awful.
The inevitable happened when Dad was killed. Dora helped her mother plan the funeral and they cried and mourned the parts of him they had loved. "He was quite lovely in a lot of ways," Mum said several times.
Dora asked Remus if they could look in on Mum a few days later. She arrived first and started walking to Mum's door, but she saw that someone was there before her. She stood behind a tree and watched the Headmaster of Hogwarts knock on the door. Mum opened the door, and the look in Mum's face was all Dora needed. Snape asked her something, and she smiled and nodded. There was no mistaking the way both of them stood as he leaned down and kissed her. Dora's tummy went all swimmy from it. Or maybe she was hungry.
She heard the pop of Remus Apparating just as the door shut with her mother and Snape inside the house. "You know what?" she said, "I'm hungry. Let's go get some Chinese."