Well, my heart goes out to you. It sounds like there's a million reasons why she acts the way she does, but I can't help but ask if there is a big reason missing? Your DH leaves for long periods of time then doesn't support the discipline structure that YOU've put in place. I don't know if that will work. You and your DH will need to get on the same page at some point about what the rules are, what the consequences will be, and what she can expect to hear as a response from the both of you regardless of whether he was home to see it or not. At no time should any adult responsible for a child be treated less than they treat a teacher, a neighbor, or daycare worker.
While not a conventional suggestion, and if he needs proof (though he should trust you and it says a lot that he doesn't), record her with your phone while she's laying into you one day so that he can listen when he gets back. If the two of you can not agree on those three things, then you may need to disengage - step back. Then you can let your husband and your SD know what you need to have happen in order to re-engage. You don't deserve to be anyone's punching bag or doormat without your permission.

I am sending good energy your way, and hope this helps.

This dynamic is such a horribly sad yet incredibly common theme in step families. It boggles my mind.

Hello and welcome! This is a very difficult problem to solve, but basically you need to find state or private agencies that deal with at-risk youth and convince them to place her in a residential facility ( could be a group home, could be some alternative school). She is out of control, and there are 4 other children in the home. Do not wait for her to discover illegal drugs. Find something like Advocates for Children, your county mental health program that works with kids at risk - i do not know what is available in TX, it may not be much, but there are people out there who can help you - it will probably be your job to find them.

She needs to leave, learn how to cope with her emotional turmoil by not taking it out on others, and then she can return once she is able to follow the rules of your home. Not addressing the problem more aggressively right now will only make it harder to deal with the issues once they become even more entrenched.

Good luck! I feel for you.

I haven't got any answers, just sympathy. I had a silently rebellious 15 year old SD in residence rather than an openly defiant one - by which I mean she was rarely rude to my face but snuck around breaking rules all the time. I also had a husband who often chose to let things go or give her the benefit of the doubt even when I felt strongly that something needed to be done.

I understand the tension and anger and frustration which increases until you start to feel uncomfortable even being in the same room. I got to a point where I would be filled with dread in the hour before she got home from school. And I started out both liking and loving her! Even at the end I had a lot of sympathy and affection but I couldn't live with her any more, not least because DH and I were in conflict over how to address her issues. The stress was affecting my ability to parent my own small children - I was taking things out on them by being short tempered and over emotional because I was so overwrought about SD. I was lucky - she was able to move back to her mothers house, I don't know what I would have done otherwise.

Regardless of any rule breaking that might occur at GM's it seems like it might at least give you a break if some weekends/weeks could be scheduled at her grandmothers on a regular basis. Or if DH could take her away for father daughter weekends/weeks. Other than that it seems like all you can do is keep rules to a minimum and hope she eventually sees the light and grows out of it.