You say OP, in your opening post, that you are considering leaving home and going to your mum's or your DSs? So I take it you have an older son who lives away from the family home? And you say that you would then let DD and your husband 'get on with it and live happily ever after'. No, No, a thousand times no....you get strong lady!
I don't like the fact that this young lady tells you, her mother, that your husband (her dad) should have picked any one of all the other girls he's had! WTF? How on earth does a daughter, a 12 year old, know about 'all the other girls' her father's had?? Has he told her this? Have you?
There is a huge lack of respect here, for you, mum, from this girl. Hormones, etc aside, you need to let her know: that you will not be spoken to like this again. That if she does this, you will ignore her, and walk away. That you will not leave YOUR home, but that she will lose her phone/lap top/whatever for a day or two (you decide) if she speaks like it again.
You tell H that you expect his total co-operation and support with this.
You also tell her that you love her dearly, and feel that there is more to all this anger so when she rages, ignore the words (directed at you) and target the rage: say, 'you sound so angry, why are you so angry?' if she makes it personal, about you, then walk away. And repeat.
Also, tell her that the last few months have been hell at home, and things are changing, and it will be positive, but that she will be taken to see her GP to discuss the impact of her behaviour, and to refer her/you/the whole family for counselling. This will make her realise that things are unacceptable, and she will get the support she may need.
Tell her that you intend to talk to her Head of Year, Pastoral supporter or whatever they have at her high school, so that they are aware of her behaviour, and support her. This school involvement will hopefully uncover any bullying issues (believe me, they've heard it all before, and know what to look for). It could well be that she's being bullied, so is bullying you - still, it's unacceptable.
Things won't change unless you change how you handle this. You're the parent, you take control - reinforce your love for her, tell her that her behaviour has to stop, because it's incredibly painful for you. Tell her you're not going anywhere - and that you will access as much outside support for her as possible. And do just that.
And in the meantime, stick a cheery smile on your face, and let her see that you are ok, and her words don't hurt you. This takes enormous effort, but fake it as best you can.
Good luck
Saffysmum (4 teenage kids 'been there, got the T-shirt' to prove it).