Before I came to F95, I just considered swinging and sharing to be a thing some adult games had, but didn't realize how super sensitive people can be to it. I think that swinging and sharing can make for a better game IF it is written correctly and used correctly. It definitely has a lot of potential to be a more mature and complicated theme.
So here's the thing - I don't have any current plans to do swinging or sharing, but if I did include something like this, it would be sharing and it would be in the Bard or Druid route, because that's where it would make sense. However, if I ever did include sharing, there would always be a choice not to select it. If I'm designing HEROES OF CELTICA so players can make a virgin playthrough, then you will be able to play it and avoid any of the sex content, too.
In the Irish mythology, the women can sometimes be objects for the men, but also sometimes crafty free agents. Queen Maeve, one of the main characters of the Ulster Cycle of mythology talks to warriors she wants to recruit by offering "the friendship of my thighs". I thought that was a funny line.
In version 0.4.0