Why wouldn't we be able to discuss it? six is a completely valid topic. In Baldur's Gate 2 you could even impregnate one of the characters.
@ OP:
In what way is six with prosttutes better and more wholesome that six with your lover? It makes no sense.
For one, six with a prosttute costs less
... anyway..
Folks, number one:
a role playing game is not meant to mimic life. It i merely that a game allows you choices and these choices affect the telling of the story and the outcome of the story. It is not supposed to be this fantasy world where you live through your on-screen avatar and all the choices you get in real life are available to you and you can have a family, or sweep floors, or need to eat, etc. Again, I blame James Cameron...
NOW, just like any book, or movie, or TV show, etc., video games have
themes, and
settings, and stories to tell based upon said themes and settings. The appropriateness of any topic (should) greatly depends on the theme and the setting of the game.
Take a game like L.A. Noire. I saw on one CF a post complaining that gamers cannot play as a female character in L.A. Noire. The lead character in L.A. Noire is a detective. Well, L.A. Noire's setting is 1940's Los Angeles. There were no female detectives back then. So certainly playing a female character makes no sense, because it is out of place within the setting of the game.
Or take a game like the Witcher, which is based on a series of books, and in the books, a big part of the story is that the lead character is a womanizer. So, the portrayal of casual six in that game makes sense.
In Skyrim, I don't think that the theme and the setting supports "romance" or "six". I don't care whether it is there or not; it is not going to make or break the game for me, but there is no good reason why. Some people will say "immersion", most mis-used word since "disrespect". "Immersion" now means "all sorts of mundane things just like real life that I see on other games".