Quick history - I've been with dh for nearly 6 years, married for 18 mths and we have a dd aged 4. He has a dsd 11 who lives with her mum (they split when she was 2) and I have 2 x ds's who have both left home.
Dsd has never particularly liked me it would seem, and has always been distant and rude unless she wants something. Her mum has never worked until recently, and this is causing lots of probs now. Although I'm glad she's working!
Dsd always came every weekend on a Friday night and went back Sat evening. Recently, since her mum started working weekends and needing childcare, she's been coming all weekend but every other weekend. All fine!
Now her mum has changed her work pattern and works every 3rd weekend, plus still wants us to have her every other weekend. So we're getting her two full weekends on the trot and then one off. Not fine at all!!
All this has been agreed without any consultation with me. I am in effect her unpaid childcare (I pay a child minder!. It wouldn't be so bad if dsd actually participated in family life, but she doesn't in any way, shape or form. From the moment she comes she's sullen and rude. She's has her earphones in and is on her I-pod touch or laptop. She totally ignores dd (4) who is actually pleased to see her sister! This results in dd acting up as she doesn't understand what's going on.
I am pretty resentful of her behaviour but work hard not to let it show, and to include her in everything we do. I went and picked her up this weekend as dh was working, and despite arranging a time, I was stood on the doorstep with dd for over 15 mins. I then didn't even get a hello, and got one word replies to my questions. I gave up!
We went out to dinner yesterday and she was vacant and didn't say a word. Dh actually got very cross with her as she was incredibly rude to him.
When she went home, I went upstairs and her bed was unmade, glass left up there and blind still down at 6pm. Wasn't impressed!
Dh and I actually had a pretty frank talk about her rudeness on Saturday and he says he's going to talk to her. I also pointed out that in 5 years I've never had a birthday card from her, and I think it's his job to ensure this happens! I go out of my way to make sure she has a card for him, and my boys wouldn't dream of forgetting his birthday.
I sound a right miserable mare, but I'm feeling pretty put upon at the moment and quite unhappy. I work hard all week in a job I don't like because the hours work with dd and it's well paid, and now my weekends feel miserable too 
. We're ttc'ing and I'm sat here wondering if this is the right thing to do.