I haven't finished reading them all either but here is my two cents.
The girl and you were close once. I think you should work up the courage and patience and dig deep for the love you felt once.
Sit down and talk to her. They may seem like they are not listening at this age, but they are.
Use love with the talk but be truthful. Tell her what you would like for her. How you would like her to be when she is an adult.
Share your vision and your hopes for her.
Explain your worries, concerns and pain for who she may become if she continues down this path.
Tell her you love her. Let her know she has hurt you beyond belief.
Don't make her feel guilty, just give her the truth.
Let her know that you would love to be able to control her actions, her thoughts and where she goes and what she does.
But that you can't. That is up to her. Her choices are what will make her the woman she becomes.
You can watch her like a hawk, but she will do what she wants to eventually.
Ask her to write down what she would like to see in her future. Find out what she wants for herself. Does she even know?
Is it college, marraige or freedom? Ask her to write out a plan of what she can do to make that happen.
Make her think about her future, not just about her present or her past.
Let her know you are just trying to help her get where she would like to be eventually. But that it is all up to her and the choices she makes.
Put the responsibility back onto her for her future. And then let her choose her way.
Be honest with her and let her know what some of the choices she chooses could lead to.
Pregnancy, disease, drug addiction, jail. Tell her this is what you don't want for her.
Let her know that you have rules for yourself and boundries that may not be crossed. That you will support her if she can respect those and if she can't then she will have to look elsewhere and deal with her choices.
Some children feel powerless over their life. Especially at this age. Not a kid not an adult. Not able to make all good choices.
I make sure I let mine know. Your choices are yours I cannot control you. I have rules, but you make your life. What is the life you want for you?
Talk with them when they are willing. Leave them alone when they don't. Tell them you love them and mean it. They know if you are lying. Just because you love them doesn't mean you like them or what they are doing.
And then let her go. Give her the freedom to make those choices.
If it means staying with her mother then so be it.
I would have an open door policy as long as it was not being abused.
Go if you need to, but when you are here follow the rules. If you can't then stay with your mother.
When kids start making choices for themselves and seeing the repercussions (and don't be so quick to bail them out, they need natural repercussion for their actions to teach them not to do that)
that is when they start to grow, learn and make better choices.
Help her when you can, but don't let her rule your life. Or worry your life away. Let her live hers.
Typically I would not want this for my child, but some are more bull-headed than others.
When they are constantly bailed out of situations they create then they do not learn natural consequences of their actions.
But try to always use kindness, love and patience.
When you remove the blame for her actions from yourself, then you will be able to handle it better.
You are not a failure. She has her own free agency to become who she chooses and you and everyone else are not to blame. Just her if her choices are not good.
I am so sorry that you are having to go through this.
I would first speak with the DH and voice your feelings. You both have to be on the same page. He can't blame you or put this responsibility on you alone. He is her father. Then sit down with her and talk.
Enjoy your time with your husband. Have fun, keep close. Laugh, play and work together. Keep your relationship solid.
Good luck.