Unknown to all three of them, but known to other people who knew them, Jon (whose name was Jenna now), Karyn, and Athena were all in a three-way lesbian relationship.
Since polygamy was the norm, however, this wouldn't be such a big adjustment for them, since Karyn and Athena had already done some sexual acts with each other, but (of course) always with Jon as a boy, not as a girl. That part of their relationship would be new.