Karisma: When it comes to sexual morality, women whether they be royal or non-royal have always been judged more harshly than males. Merrit Marit was judged more harshly than her husband would have been if he had done the same things that she did. A male royal could have girlfriends who are of questionable character, father a child out of wedlock, do things that others in his age group do, and unless it involved terorism, murder, arson, or some serious felony, he would basically be given a free pass. The woman he had the child with would face judgement, but not him as much unless he didn't pay child support.
If he was the heir to the throne, the fact that he dated women of questionable character, fathered a child out of wedlock or did things which weren't good, would never been brought up against him nor would others use it against him to say he would unfit to a be the next King. Perhaps because the governments are ran by males who have might have done the same or similiar type things, you can't exactly throw stones at glass houses. It could be thrown in their face if they made an issue of it.
It would be very interesting in the future if a female heir to the throne had dated or became involved with men of questionable character, had a child out of wedlock, or admitted to doing some other youthful things, I wonder what the response or reaction would be of that country or the government of that country. She wouldn't be getting a free pass. If she posed nude, she would probably be dethroned or people would say she would be unfit to be a monarch. A monarch or heir to the throne who dated a woman who posed nude would not get such punishment. If he married such a woman, that might became an issue (again the woman would be judged for doing this, he wouldn't be judged because he dated her or wanted to marry her). He's just having a good time would be the reaction to this.
That is just my take on the question if women are judged more harshly and the answer is yes, most of the time.