I'm new to this and a bit nervous about posting. I'm in a relationship with a wonderful man (been together 3 years now) who has an 11 year old daughter. I feel like we have done everything with care and caution when it comes to bringing me into her life. I met her for the first time after 6 months. My bf has her every other weekend, at first I would just meet them for a day out or meal, wouldn't stay over etc. Fast forward to now, we are living together. My bf and her Mum broke up when she was 1 and her Mum now lives with her new bf who also has two children who stay regularly with them. While me and my sd get along I just don't really feel like I have much of a relationship with her and generally feel a bit useless. I've never tried to be her Mum, she has one who she adores, and she adores her Dad as well. However she doesn't treat out home as hers and we still go to his parents every Saturday night we have her, to stay over and generally stay there until 5pm Sunday when we leave to take her back to her Mum's, because this is what my sd wants. Her attitude is appalling and she'll very often scream at my bf that she never wants to see him again, she's ashamed of him etc and I have to sit there and listen to it. She says he babies her however she plays up to it- baby voice when she doesn't get her own way, cries about 4 times a day, seems to invent 'poorly tummies' quite often for attention, won't go to sleep unless he goes in and lies with her in bed... am I wrong to think this is a bit strange at the age of 11? I know she's seen a few men come and go with her mum, and the only stable thing she has had has been every other weekend at her grandparents however I honestly think part of the reason she wants to be there is because she gets spoiled rotten. We go there and she picks what we all eat, what films we watch that night, what we do. I never get involved when she's misbehaving, the one time I did, last week, she went straight back to her Dad, in tears, and made up stories saying I'd shouted at her and told her she couldn't do something. Luckily he saw through it and very calmly backed me up and she admitted that I had been right. This is a really long post but I just wondered if anyone felt similarly to me- I just feel useless and not relevant to the situation and while I'm fully aware she's a child and I'm an adult it's hard not to feel a bit resentful at times. We would like to have a baby together soon but I don't think my sd would take it well at all, we've talked about getting married but I can honestly see her creating a scene at the wedding.
I may sound selfish, and I'm trying so hard not to be, but I'm struggling with the whole situation.