I see nothing but trouble in Your future with this - You have
"expressed Your concerns O F T E N but nothing is changing"
So, there lies Your answer - accept things the way they are or leave it. Don't make Him, the Daughter or YourSelf miserable by trying to "change" it.
I'm not saying They are right or wrong but it IS Their style and You're as likely to change it as He would be to change YOUR parenting style.
GoodLuck
Well.........this has to do with parenting styles. You have only been dating him for 9 months and the relationship is too new to be giving your input about his parenting skills. I would say this child has been through a lot already, i.e. parents aren't together, and that would explain her behavior. Remember, she is only 8 years old.
"I have expressed my concerns often but nothing is changing. He has stated that he will sleep with her until she no longer needs him to."......He has already told you how things are going to be, so.......your choices are either stay and deal or leave and not deal. There aren't going to be any changes UNLESS you leave.
If it is bothering you this much then you need to reevaluate the relationship to see if all this is worth you staying.
You haven't been in his life or his daughter's life that long to be asking for this to change. I really can't see why it should change.
You aren't going to be able to change how he interacts with his daughter because they've already had 8 years of this kind of relationship before you ever came along and they're not just going to change for you. But if you have any kids with him, then you're going to have to figure out how to raise that kid in a way that reflects both of you.
It's pretty clear that his parenting is very different from yours, which can become a huge issue when you try to blend families. I don't know what your intentions are with him long term but, if you plan on getting married at some point, then you're going to need to get on the same page first. Otherwise be prepared for lots of fights and lots of problems in your future.