Child support?

Do you think it's fair for a woman to take half of the dad's paycheck for childsupport? He isn't a deadbeat dad. He doesn't owe back support or anything like that. Her and her husband both have great jobs. But with all the money they take out of the father's check he can't afford to pay his rent or he can't even pay for food. She is planning on taking him back to court for even more money. Do you think this is fair?