My sister in law was an aguna for a long time. Her ex husband refused to pay support, yet insisted on visiting rights. There are cases where the wife paints her ex out to be an evil guy and brainwashes the children into her way of thinking, however these are not as common as we think. Very often the wife withholds visiting rights because the ex is not capable of responsible fatherhood.
Actually, Family First’s new serial addresses this issue.