I believe your stitch is the exception and cannot be given the same advice that would ordinarily be given. Your W wants her freedom. She was never allowed to grow up from a normal teenager into adulthood. You surely can see that.
She is angry that you took advantage of her.....and you did. She may have went willingly, but she was a CHILD and you were the adult. Between you and her mother, I'm sure it wasn't hard to convince her that her life would be much better living with you. You know if the law had been called, you would have been in big trouble taking this girl and having sex with her.
I can't support this b/c I believe you were wrong as sin in what you did. Give the girl her freedom and allow her to chose a life for herself instead of what others tell her to do.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!