Well here it goes.
Do you remember all the times I was insulted by your daughter and you said nothing? When I wanted to set simple rules for her and you said she is just a child?
When I wanted her to cut out her cursing and you were proud that she talks like an adult, you called her witty? A ten year old cursing is just nasty not witty! Disgusting! When I wanted her to take showers regularly and you said don't be so hard on her. Dirty clothes all over the bathroom, shoes behind the toilet? Aw come on now, just put them in the hamper, NO she can just put them in the hamper!
When I get angry because she won't flush the toilet, I get up in the mornings and there are turds in the toilet and a nasty smell, and you told me not to make such a big deal out of it, to just flush it.
You also told me to just take the dirty dishes out of her room and not be so uptight.
You got mad at me when I refused to help her study for her test at 8pm, because all week she did not listen to me and study, I told you she is not studying for this important test, do you remember what you said to me? You said hmmm. When I tell her to clean her room, you are telling her in front of me she does not have to, how do you think that makes me feel?
When she uses my things without asking, and then they are either missing or broke.
If I would do all those things to her, you would chase me into the hills.
The world does not revolve around princess, I'm sorry! You made her an equal partner in our relationship, guess what she is ten years old! You hear ten!She is your daughter, not you partner, not your friend.
We are the adults, we are supposed to be making the rules here!
I'm tired of her talking about her mother and new boyfriend all day long and the two of you making mean jokes about them the whole time she is here, it's getting old.

You will remember my words when she drops out of school and goes down the wrong road,just like her mother, only then it will be to late.
I tried, I really did try hard, she responded well to me but you threw a wrench into it. What were you afraid of? Do you remember how happy she was when she brought home her first B, after we practiced so hard? Did you see how proud she was when I thought her the multiplication table?
She would say sorry if a bad word slipped out of her mouth, she stopped interrupting. We started to get along so well until you undermined me. You were afraid she wanted to go back to her mother if she can't do as she pleases.
Well she did go back to her mothers,and I am not ever doing this again.

At her moms she causes nothing but problems,because her BM is just like you,her new BF wants to set rules...it's a cycle. She can't keep on manipulating people. Her own brother, your own son, can't stand her..why you think is this? Maybe because she lies to you about him hating you? Because she told you he likes his step dad more than you and you are so stupid believing this crap. She destroyed your relationship to your son, I hope that you one day see he is a good kid because he really is.