In some ways, Molly Prewett Weasley was the most traditional pureblood witch of them all.
Children were a gift. Molly wasn't sure if the old gods were real, or any god at all, or if magic was a sentient thing capable of gifting children and blessing witches and wizards, or if everything just happened with no greater guidance. But she believed, as the witches and wizards of old had believed, that magic was a gift, children were a gift, and magical children were a special gift.
It was said (in some families and regions) that magical children were a gift given to those who were worthy of having them. If you were deemed unworthy by the deities, or magic itself, you could not have children. If you were a good parent, but delved into the wrong magic, or mistreated it, you got a squib. And, for unknown reasons, some muggle parents were gifted with magical children. It was thought it was either because they were special muggles who were suited for raising a magical child, or had pleased the gods in some way, or maybe that the child itself was special enough to survive superstitious muggle parents.
Of course, this clearly wasn't entirely accurate. The Blacks had had a couple of squibs pop up, and they generally weren't fantastic parents, disowning them as soon as possible. And muggles, in time gone past, didn't look very kindly upon magic, and didn't deserve their special children at all. But Molly still believed that children were a gift.
To prevent a gift? To stop it from coming? To stop magic itself from coming into the world? That was surely wrong. Others could do as they wished, but Prewetts took children as they came, and loved and celebrated them. To be fruitful was to be blessed by magic itself, and to go against this was surely wrong.
Molly wasn't sure how much of this she believed. Her mother hadn't believed any of it, but had agreed children were special and that one shouldn't use birth control. Her Grandmother had been the one to tell her the stories of Brigid, the Irish goddess associated with fertility, and all her incarnations in the different cultures - Roman, Greek, Welsh, Germanic. Her grandmother had believed in the old gods. Molly wasn't sure, but she agreed with her mother. To deny a life from living was wrong.
Arthur amiably agreed. Weasleys didn't use birth control, either. Weasleys had large families, and children were adorable.
And so, seven children were born to Arthur and Molly Weasley. It was hard. Arthur, while a most devoted husband, and an adoring dad, wasn't much of a father. Several times, Molly urged him to consider taking a higher paying job, but Arthur, a man of principles, insisted that his work in the Misuse of Muggle Artefacts was too important. Molly agreed. It was very important. Unfortunately, the hours were long, and the pay was inadequate.
Arthur could not see the point in sending the children to primary school. "But dear, you're an excellent teacher, Bill's an entire year ahead, and Percy will be no trouble to teach at all. It would cost far too much, and it's not as though you have a job."
When Molly suggested that she find work, and a babysitter for the twins, Arthur got angry. Weasleys didn't accept charity, and Arthur's wife didn't need to work to help support his family.
Molly didn't want Ron. She cried when she found out she was pregnant. Arthur, when told, happily said "Oh good, another baby!", but Molly privately worried that she might drown the twins. She stopped carrying her wand when she was seven months pregnant, scared she might curse Bill or Charlie, and felt what a horrible mother she was. Her postnatal depression was horrible. Although Arthur never said anything, she could tell by the tightening around his eyes and the set of his jaw that they could not afford many St. Mungo's visits, not during wartime. She considered taking a contraceptive potion, but was too exhausted to even have sex for the first five months. Of course, with her luck, she fell pregnant with her seventh child when Ron was seven months old. Too tired to even cry, Molly decided to place her faith in the magic number of seven, and sure enough, Ginevra Molly was the first Weasley girl to be born in years - and the war ended three months after her birth.
(Strangely enough, it didn't help the depression.)
She was also the last born to Arthur and Molly, to the relief of both. Bill was starting at Hogwarts soon, and Arthur was discovering how much books, wands, and robes cost. The war was over, and life was going back to normal, and normal life with seven children was hard. As a member of the Order during active wartime, Arthur hadn't spent much time at home while children were going through day to day life, and he hadn't realised just how much work it all was. Fortunately, the post-War time was still very busy for the MoMA, and Arthur was often out late at night, conducting raids as Death Eaters undergoing trials or under suspicion desperately tried to hide all Muggle baiting and Death Eater paraphernalia. And if that meant he was too busy to spend much time at home, well, seven children were quite a lot for him to deal with.
Arthur was willing to play with the children, do the fun stuff with them, but once they began screaming, Arthur was out. He didn't intend to dodge doing his share of parenting - he just assumed when children screamed, the mother dealt with it. And he couldn't discipline to save his life - or Molly's sanity. The flying car incident really just about summed things up - the children did something very wrong, that could have had terrible consequences, and Arthur refused to discipline them, or even take it seriously. If he had been more responsible about it, and been firm, and explained to the children why it was so reckless and dangerous, or even at least understood himself, Ron would never have taken the car to Hogwarts later! And look what happened - Arthur himself got in trouble.
The truth was, Molly really had eight children to look after. Arthur insisted his job was important, too important to leave for a better paying job, yet all he really did was use it to break the laws he wrote himself. Oh certainly, he wrote some important laws that protected Muggles, but his car at the time had been one of the biggest dangers to the Statute of Secrecy for two years. And she was viewed as the shrieking harridan, kicking up a fuss over nothing. The boys rolled their eyes at her, while Arthur winked while she wasn't looking.
And when she bought them their second hand books, clothes, robes - she was the one they grew sullen with. Magic helped a lot, but could only do so much. She knew how Ron hurt when she bought the only pair of second hand dress robes she could find that would fit him. It couldn't be helped. The twins were able to partially pay for their own, and they were a fairly standard size - average height, only slightly burlier than the standard male robe size, and Ginny - second-hand little girl's robes were a dime a dozen. Tall, lanky men tended to get one set of robes, and keep it forever...whereas rich girls bought and tossed aside robes like they were pewter cauldrons. Ron would have looked far more ridiculous in a robe sized for the twins - too short, and too wide. She knew this, because Ron had often needed school robes the same size as the twins….making that three sets of robes she usually had to find in a similar size. Damn those lanky Weasley genes. The Prewett-esque children - Charlie, the twins, Ginny - generally looked much better dressed simply because they were a more standard body type. Poor Ron was inevitably stuck with his wrists and shoes showing.
Charlie didn't mind second hand things too much, being more animal focused than social, and Bill was cool enough to pull off anything. She thought that might be partly why he went with the punk look - it fit with his worn robes, scruffy shoes, and torn jeans.
Percy, neat child that he was, minded much more. He learned many spells from Molly and her books - mending charms, tailoring charms, ironing charms - everything possible to make him neater and make his clothes and books last longer.
The twins were always asking for more pocket money, and once they accepted it wouldn't be coming, started looking for ways to make their own. Usually, it involved trying to score Ron and Ginny's pocket money. They didn't care, they claimed, they were able to make it on their own. They were good enough beaters that the brooms didn't matter. They were businessmen enough to find their own source of income.
Deep down, they almost believed it.
When wartime came again, Molly thought she would go insane. Everything was falling apart - and Molly had spent all her adult life trying to keep everything together. Her home was falling apart - they often found themselves having to stay in Grimmauld Place, which was pretty much the textbook example of 'falling apart'. Her family was falling apart - Ron was distancing himself, loyal firstly to Harry, Ginny was fast growing up and slipping out of her reach, the twins were pushing themselves ever closer to the edge - opening taunting You-Know-Who! Charlie had been distancing himself from the family for years, and Bill - Bill was marrying out of their social status, and Molly was terrified he'd look down on their unsophisticated country home and their working-class associated accent, compared to the glamour and sophistication of the French family of Veela and successful politicians. And now Percy was following Charlie's footsteps, only much more openly. Charlie abandoned them for his beloved dragons, out in the middle of nowhere - Percy was openly rejecting them. Percy was openly despising his father. She thought her heart would break. She tried her hardest to keep him part of the family, but all her attempts were rejected.
When she saw Bellatrix Lestrange tormenting her teenage daughter, something in her snapped, and for the first time in her life - the very first time - she felt hate. Molly had felt many, many emotions in her life, but never true hate. All her rage, all her hurt, all her grief - for Freddie, for her brothers, for her family, for her friends, for Harry, who had walked into that forest to die - and all her love, all her insanity, all the darkness inside of her rose up and poured out into the killing curse. She hated the woman, the antithesis of all she was - and in that moment, that one moment, there was little difference between Bellatrix and Molly.
After the war, Molly was hailed as a heroine - an example of the power of maternal love, the defeater of Bellatrix Lestrange. But only Molly knew how close she'd come to snapping, to losing herself. It was love that killed Voldemort, true...but it was hatred that killed Bellatrix. The Killing Curse cannot be fueled by love.