Is Yosuga No Sora set up like.... (Spoilers)?

Well i was wondering this too. Many sites and discussions are saying that its going to be more like some sort of betrayal but there is still the hint of doubt that it may end up as the dating (which would suck entirely). But we may just have to wait till episode 5 to find out their approach. Also, school days is an anime you might enjoy but just warning you...Its kind of messed up