As the dev stated earlier in the thread, there will be some chances for group sex/threesomes coming up with different interesting combinations of LIs...it remains to be seen if any if these opportunities will lead into throuple/poly-relationships or some kind of mini-harem. It hasn't been completely ruled out, though some LIs will be more reluctant or more willing to share than others.
As frustrating as it is, we might as well keep playing till there are some more obvious warning signs for dating multiple LIs. Since I started over from the beginning with this last update, instead of playing multiple saves/LIs, I'm just playing for a main LI (Julia), but still going after others with love/lust points on the side...and whatever happens...happens.