alright geezer

All three Black sisters are in love with their husbands (or...whatever love looks like to each of them). The way I see it, Bellatrix does nothing she doesn't want to do. If she didn't want to marry Rodolphus, she would have murdered him. Or, she would have married him and then killed him and kept the gold. Personally, I think she and her husband want to fuck Voldemort which is what made their union so, so special. (Maybe they had a threesome and that's how Delphini came along, idk. Or, let's be honest, maybe Rodolphus asked to be in the cuck chair while his wife and Voldemort fucked...)

Narcissa and Lucius struggled with infertility, and so, Draco is their miracle baby boy most precious thing in the universe.

Andromeda and Bellatrix were best friends and only a year apart in school. Andromeda dated Ted secretly, and when Bellatrix found out, they had a huge, explosive fight. Following this, they never spoke to each other again.

Narcissa snitched on Andromeda and Bellatrix all the time to their parents or house-elf.

Bellatrix isn't insane. I don't know how this came to be some sort of "accepted" truth about her, but she reads, to me, as someone who is incredibly cruel and angry and intelligent. She's someone who gets bored very easily, and she isn't bound by a sense of empathy to keep her actions in check. She seeks praise from Voldemort because her self-esteem is derived by her belief that she is inherently better than everyone else--but she's extrinsically motivated by how she is perceived by others. Voldemort feeds her need to be appreciated, and thus has her undying loyalty. I see Bellatrix as a very Azula-like person, and it might've been nice to see that kind of arc for her. Alas.