I moved in with my ex 16 years ago when her daughter was 3. I’ve tried to help my daughter see society for what it is. I’ve helped her with her interests. I’ve been a very active and fun father. A couple of years ago, my daughter started liking pop culture that I could not get into. She started treating me like I was an idiot. When my ex and I figured out that we’re too different to be lovers, my daughter thought her dreams had come true and that she would never see me again. She’s pretty upset that I still live in the same house as and communicate with her mother.
I would suspect there's more than just pop culture creating the problem.
Do I have this? When you were thirty-six, you moved in with a woman, and her three year old daughter....and after sixteen years, ...you and the mother are no longer lovers, as in a couple, but you continue to live in the house. And after sixteen years of being an active, and fun, father....the daughter has turned on you.....am I missing something???
This is temporary. As a teen, her developmental job is separating from her parents. It's hard for parents.
@ToolGuy is correct.
"I hate you!" my daughter Claire raged at her dad and me when we said no. "You are not my parents!"
That didn't last. After six weeks, she came back. "This is temporary," was my mantra when Claire was a teen and in her early 20s.
At 29, Claire is respectful, appreciative, thoughtful and loving.
This is a very tough situation for you and it cannot be easy. Try to make allowances for her youth, and like @Athena I believe this will only be a temporary blip in your relationship with your daughter. Even if she were your biological daughter you could be getting this treatment from her at the moment, I know lots of parents who are treated with scorn and derision by their teenage children...I remember my husband and I seeming to be a constant embarrassment to our boys, who acted like assholes for a period of time. Try not to let this get to you too much, if you can discuss it with your ex wife ...presuming you are on good terms, as you’re still under the same roof, it may be helpful. Best of luck, and just keep trying to be a good Dad.