C.M.
Believe it or not, my stepdaughter acts up when she feels like she's not part of the family. Going between two houses is hard, and sometimes kids feel like they're not part of one house or the other.
Recently my SD has been acting up (is it the weather? Back to school?) When I finally sat down and talked to her about it she said she felt bad because her mom had gone out and had family pictures taken with her, her boyfriend an her brother and sister. My SD was at our house when they did it so she wasn't in the picture. Her mom had said she was going to Photoshop my SD into the picture (and she did) but my SD was very hurt that she wasn't ACTUALLY in the picture (even though the final product looks like she was) and wasn't able to go with for the family picture. At the same time she heard that my husband and I had gone out to see a movie she wanted to see. We weren't going to let her see it because it was rated R, but she didn't know it was rated R and so in her mind she felt left out.
Sometimes stepkids need to feel like they belong and are important. They don't need toys or outings, they need LOVE. Sometimes they just need someone to sit down and listen to their side, even if it sounds silly to you.
It sounds silly to us that my SD would be upset over a picture when it looks like she's in it and upset about a movie she wasn't allowed to see anyway. But she was, and that's her world. All we needed to do was listen and give her a hug and tell her she is loved.
Good luck!