F.,
I'm wondering if the first part of your message did not come through and if I have most of the information. (?) It's good that you are seeking help because your relationship is certainly worth it, especially if you will be marrying. It sounds to me that the daughter is feeling very insecure and this is coming out in an immature way. Your initial reaction is likely to be annoyed by it, which she will sense, and this may cause her to act out even more to "win you over." It sounds like she wants to be viewed as important by you. If you haven't yet, try to win HER over. Show her that you care about her because she may have been getting only negative signals from you even if you didn't mean to show them. She needs to know that she will be valued by you and an important part of your relationship with her father. If you and he are talking about something, and she interrupts with something directed to you, say something like, "That sounds really interesting. As soon as I finish talking with your dad, I would love to hear more about it," or "Just a minute, ok?" with a smile on your face. And mean it! Let her know you care. It will make a big difference to your fiance to know that you genuinely like and care about his child, and that will help your relationship with him when it comes to discipline and wanting the best for her. I really think she is crying out for your attention and approval. Spend some time with her one on one. If she knows that you really do like her, it will make her feel good about herself and your relationship with her dad. Make it your goal to love this child, and you will change the two of you in the process. She deserves it.
I wish you the best.
Leeanne