Originally Posted by Her_Majesty
That's also why the CP needs the permission of Stortinget to get married.
(I don't know if the other members of teh RF need the permission of Stortinget too, actually.... does anyone know?)
The Constitution requires the King's permission only. The requirement applies to any Prince or Princess (and will likely be interpreted to apply to the Behn daughters as well) who wishes to remain in the order of succession after marriage.
A Prince or Princess entitled to succeed to the Crown of Norway may not marry without the consent of the King. [...]
If he or she acts contrary to this rule, they and their descendants forfeit their right to the throne of Norway.
Originally Posted by EmpressRouge
It's the tradition that a wife takes on her husband's titles and not the other way around. Since Haakon is the crown prince, his wife Mette-Marit becomes crown princess. Even if they weren't royal, a woman takes her husband's name. If Joe Smith married Jane Doe, they would be Mr and Mrs. Smith, not Mr. and Mrs. Doe.
It is allowed for a husband to take his wife's name under Norwegian law. Given that all married princes of the present royal house have been kings or crown princes, and none of the married princesses have been, I think it is too early to assume that Prince Sverre Magnus's wife will take his title while Princess Ingrid Alexandra will take her husband's name (Princess Märtha Louise did not).