Chris Brown attacked Rhianna in February. By March there were reports that the two of them were back together. This did not surprise me or anyone else in my field. In fact, it would have been more surprising if she did not go back with him.
Domestic violence is a scary, difficult issue. Most family members and friends get very confused when victims keep going back to their perpetrators time after time after time. It is difficult to understand the dynamics of such a couple.
A perpetrator usually has convinced the victim that she is valueless and powerless by the time the violence starts. Not only that, but it is her fault that he hits her in the first place! (I will refer to the perpetrator as a man and the victim as a woman; however, please be aware that a woman can be the aggressor and the man the victim.)
One of the things that can keep a woman captured in this relationship is the cycle of violence. First is the tension-building phase. The man is getting increasingly angry and stressed. The woman is getting increasingly worried and stressed. Then the violence occurs. After that is the honeymoon phase. The man feels terrible. He tells the woman that he will never do it again. He tells her how much he loves her. He often gives her gifts. He romances her back into the relationship. Then the tension building starts again. Unfortunately, the honeymoon stage gets smaller and smaller as there relationship progresses until it disappears totally.
People can break these patterns if they get treatment. But it is not easy. And it takes a long time.
So, have some compassion for Rhianna. And hope that both she and Chris Brown get treatment immediately.