It sounds like you are exhausted.
Emotionally and physically and for good reason.
Make a list of what you need.
Be totally honest.
Husband home more often,..
More time away from stepdaughter.
More alone time with your own daughter.
More alone time with husband.... whatever it is you really want..
Then go back and check off what is an absolute have to have, not just want. This should be the things to save your sanity and your soul.
What can you and your husband do to help you get this part of the list?
Is it working outside of the home? Is it doing some volunteer wrk away from home?
Some activities for just you and your bio child? Is it the weeks step daughter is away from mom your bio daughter and you do things alone together?
Also Counseling as a group is awesome. Make sure you are totally honest about what is going on. I also suggest you by yourself get therapy.. You may be a little depressed, which is not unusual for women your age, but to have all of this stress, cannot be helping.
Make sure you are getting exercise and running errands and cleaning the house is not exercise.
Be good to yourself. Do not take your stepdaughters behaviors personally. These behaviors are not in her control and may never be. Instead help her try to figure out solutions on reminders to help her become part of the larger group of our society,. 10 is still young, so it will probably be a while till some common sense and control of her behaviors are under some sort of control.
The good news is that our daughter has had some friends with these types of problems to over come and each and every one of them graduated from high school and are either in college or working full time. No pregnancies no drugs and no drinking problems.. Their parents work very hard to help their children be the best they can be. I admire them so much.
I am sending you strength.