1. She's a preteen girl. Those preteen & teen years suck for everyone involved. Do some reading on preteen and teen girls. There are lots of materials out there to look at, especially web articles.

2. It sounds like bm is out of the picture...sd may well see her friends with loving moms and wish she had that. She may need professional help to deal with her mom's lack of interest in her.

3. She needs to know her dad loves her unconditionally and a dad who spends time with her, but won't tolerate her bad behavior towards you or anyone.

He is giving up on her by refusing to set appropriate boundaries on her behaviour. As anon2009 point out 12 can be a turbulent age for a girl and does need some understanding, but, generally children want and need boundaries and the security of knowing their parents are strong and secure and loving enough to maintain them. When your child behaves badly and does not get appropriate consequences that gives the message that the parent doesn't feel confident enough in their parenting, or secure enough in their relationship with their child, or that they simply don't care enough.

If SD has issues in her relationship with her mother some of her behaviour may be conscious or subconscious testing of her Dad, with you caught in the crossfire. When DH and BM did not notice let alone clamp down on my YSD's behaviour when she began to act out and get sly, she escalated the behaviour and kept escalating until they noticed and did something about it. Their lack of attentive parenting and boundaries didn't make SD feel happy and relaxed, it made her feel insecure and unloved. It's very hard to deal with as a stepmum though.

Maybe your DH could use some books on Preteens, and some parenting classes to help him help his daughter. Or both of you need the support of some family counselling. Or she needs some good counselling. Because raging in restaurants and throwing furniture suggests SD is a very unhappy angry girl. And if he really cares about her her Dad needs to face up to that and address it instead of resenting your appropriate reaction to her inappropriate behaviour.

I've noticed when my husband alrdy feels guilty or down about something, if I bring it up he flips out. I think it's because he freaks out that he doesn't know what to do. I do the same thing. I always feel like I have control of my situations and when I feel like i lose it or can't find a way to keep em under control, I drown myself in ways to solve this situation. Then when someone brings out the obvious (hey there's something wrong) I just explode.
I'm not trying to justify anything but maybe he feels the same way you do, but knowing that it's his daughter and that he is responsible for this he gets even more angry when others notice it... does that make sense?
Anyways, when I was between 11-18 I was the devil to my parents (I even wrote a very nasty letter to my dad calling him a dumba $$ among other things. My dad even accused my mom of PASing me after that even though she always encouraged me to talk to him)I was just angry and unhappy about everything. .. I think it was hormones and being a teen.. idk maybe it was the fact that both my parents worked a lot and I was never thought how to deal with anger better?? Today I am 26 and am always calling my mom and my dad for advice (even though they were never married and still have relationship issues). I kinda envy my half brother and sis (born in a marriage w my dad and his wife). But I don't hate anybody anymore... hope this helps

Yes she's a hormonal, angry teen with parental issues.

But IT IS NOT YOUR FAULT. She has two parents - neither of which is you.

Ask your DH why he thinks you should parent her when he doesn't. Why does he think he can stand there doing NOTHING and expect you to pick up the pieces?

Tell him to step up to the plate and that you will not let yourself be abused by ANYONE even his little miss precious.