I can't stop thinking about a Miriel who would have recovered fine if Finwe hadn't insisted she has more children.
Just imagine Miriel, who's just gone through pregnancy and childbirth and absolutely hated both, it was an absolutely weird and alien experience, she felt her body was not her own, she was exhausted, had weird cravings and things were happening to her outside of her control and she absolutely, for nothing in the world, ever wants to go through that again. And then there's her loving husband, immediately telling her that he wants more children. And she's desperate. She keeps telling him that Feanor is perfect, that she poured absolutely everything into him, her whole Fea, her whole spirit, it was exhausting, he's so perfect, isn't he enough? But Finwe isn't listening, he keeps telling her he wants more children. And so she tries to describe to him how exhausting and horrible the whole process was and Finwe is nodding and not saying anything and she thinks he's finally accepted her wish. And then, a few weeks later, he suddenly comes to her, telling her he talked to Manwe about her problem - what problem? - and that Manwe said she'd find healing in Lorien and he, Finwe, would take the baby until she felt better. And Miriel realises with sudden clarity that he's taking her baby and locking her into Lorien until she agrees to have another baby. And nothing she says changes his mind, he claims he's just helping her, that there's something wrong with her that needs to be fixed, that this is for her own good.
And so, she goes to Lorien, leaving her infant behind. And she lies down. And finally, she gives up.
But also, imagine the effect on anyone else. Finwe never really understood what she was saying, he honestly believes she's just exhausted from childbirth, that she poured too much of herself into the baby, and then she lies down and just…fades, so it must have been even more exhausting than he thought. And now he's left alone, high king of his people, with an infant baby without a mother, and he still needs to show his people that it's safe here to start big families. So he griefs her, and he moves on. Miriel doesn't mind him marrying someone else, it has been made absolutely clear to her that what Finwe wants from a marriage is a lot of children and she's unwilling to provide. She even likes the Shibboleth, it means that, while Indis is alive, she and Finwe will never be alive together, and so it means noone will ever force her to get pregnant again.
And Finwe tells Feanor that whole thing from his perspective. Which means Feanor learns that his mother died from putting too much of herself into him, that his birth was the reason she died, because that is what Finwe honestly believes. And so everyone believes that. And Feanor hears the Shibboleth and believes his parents would want to be together, his mother just needs more healing, but now it's impossible, because Indis moved between them.
(Also, I am now imagining reborn Miriel taking aside reborn Glorfindel bevor he is sent to Middle Earth, and telling him the whole story, to make absolutely sure he spreads the correct version in Middle earth, which explains why it's formulated like that in the Silmarillion.)
(And again, I don't really think this is necessarily what happened. I don't think Finwë was the best father, but I do usually assume he was a good man. I just got caught up in this interpretation recently.)
