My little one is experiencing terrible jealousy pains. The boy has had is girlfriend over and the girl tries her hardest to sit between them or prevent her brother from getting anywhere near her or even hates to leave them alone together. I caught her standing in his doorway playing her DS game refusing to move or look at them.
Even strangers are not safe. A young couple was sitting in a local restaurant (girl on his lap) and she went over and sat at their table staring at them with huge eyes. The stranger girl got a little nervous and asked the girl if she wanted them to leave. She refused to answer and I had to call her over.
Tonight, at the mall, the boy put his arm around his girlfriend and the girl could not squeeze between them so I saw her finally just give up and she walked with her arm around his girlfriend too.
She has put aside the jealousy and has now claimed his girlfriend to be her new best friend and that they are a "girl's only" club so he cannot sit with them.
It is probably the first time the girl has not been the center of attention. Even at school, she is always in charge of a group of kids, having them play her games, stories, and inventions. It is fascinating watching her solve her problem.