Charles' and Diana's marriage broke up BECAUSE of his adultery! Diana opened a parcel addressed to Charles (yes, I know but she must have been suspicious, perhaps it smelt of perfume), and she found inside a bracelet with F and G letter charms on it. The initials of the names these two used to refer to each other as.
How would you have reacted had it been your husband? Wouldn't you have confronted him? Would have you felt ok with your husband-to-be wearing cufflinks given to him by his mistress, at your wedding? Would you have put up with him going off to meet his mistress whilst you were on honeymoon? Personally I would have called it a day then and there. It wasn't just one marriage these two split up it was two and four children, two on each side, lost their mother. But hey, that's life aye? Actually I think they deserve what they get myself. They knew exactly what they were doing.
Diana did not have affairs until the scandal hit the papers. She could have been happy if it had not been for gold digger Camilla. Who needs friends like that?
Just because Kings and Queens behaved the same way in the past does not excuse their behaviour. In the past men were allowed to beat their wives, they aren't now.