Hi everyone

I am new to this Step Mother thing. I am engaged to be married to a wonderful man this coming June. He has a 10 year old daughter. The mother of the daughter was killed 2 years ago in a tragic car accident. My Fiancé and the Childs mother were not together and had not been together for years before this happened. And the mother was not really involved too much. Basically she was only involved when it was convenient for her. They were never married either.
We have been together almost a year and along the way I have noticed some things that bother me about her and the way she treats him.
When I first came along, she was still sleeping in his bed, he was still bathing her, letting her pick what she eats etc , going to bed at 10 pm on a school night, to name a few. Basically she ran the roost.
As I became more comfortable with this dating situation, I asked him about it. He said that being her primary care giver for most of her life he just basically has done everything for her and so does his family. She is a very spoiled little girl who basically gets what she wants by acting helpless or like a baby. People just do it all for her. He admitted that he knows it isn’t helping her and has really improved with a lot of this stuff.
Her and I get along great. We have girl time, we talk about boys, or just private girl things. She has never really been rude to me. Just to him and has disrespected him numerous times in front of me. (makes sassy remarks, lies to him, ignores when he tells her to do something)
Lately since the wedding planning has begun, she has developed new behaviors that are not acceptable. She lies about brushing her teeth, or eating candy for breakfast. We give her a few chances to admit it but she still lies. He has punished her for every time she has been caught doing something like this for lying to him. I personally feel she is jealous and is acting out to get attention. Another new thing she is doing is playing completely dumb. About everything. Not knowing suddenly where her dirty clothes go, asking if eating out of a mixing bowl will help her eat faster. Just things that are completely absurd. She does see a counselor but we don’t feel the counselor is aggressive enough and doesn’t really get her to talk about her feelings. She is also very clingy with him. Tries to get him to hold her or carry her, talks like a baby to him, calls him daddy in a whiney voice, tries to snuggle on the couch with him, kisses his face a lot, tries to hold his hand the minutes she sees him grab mine. All jealousy issues. I find myself having no patience for her anymore lately and I don’t want to be that way with her. But I don’t know how to tolerate her acting like this.
I understand all of this is new to her, as it is all new to me. I’m just struggling with how to deal with all of this and could really use some advice. We are trying to avoid a whiney, clingy , disruptive child on our wedding day. HELP!