I think people often struggle with a feeling of helplessness after the loss of a relationship is because, it feels like they will never see the person again or they feel like they have lost their only support system.
My daughter lived with me for a year. I felt so helpless when she lived with me because of a manipulative personality.
I ended up asking her to leave to find a job. I felt helpless until she found a job.. three weeks later. I think we feel helpless when we realize that we have no control over the situation, but trying to trust God to work things out.