Never in the entire history of England has a divorced king sat on the throne. And even if they move the goalpost and allow a divorced king to sit on the throne, he is also defender of the faith and head of the Church of England, which doesn't allow remarriage even within the church. It's against the church laws. A lot of people say they're just human beings but the royal family has set themselves up as icons and they expect respect. They are not just ordinary people.
Ordinary people have work, monarchy people have a duty.
Really no one is going to benefit from a divorce. Diana has asked for very little. She wants to keep her home where her children are. She'd love to find a person she could really love and be loved in return. But Diana would be hesitant to marry again because she would fear loss of complete access to her children and any say in their upbringing.