Well the thought about the Prince being gay is not that ridiculous… it might explain a lot of things. JS said we were going to be surprised on the reasons he comes back… so I suppose he comes back not because he loves Blair and wants to marry her all of a sudden but for other reasons. Or green card.
Blair is into a hidden relationship with Dan, Vanessa hears them in the coffee “No one can’t see me here”, so Vanessa tells Chuck there is something weird… then Blair and Dan kiss each other, but Vanessa films them… and sends the video to Chuck. He comes at Dan’s to tell him to break up with Blair, or else he sends the video to Gossip Girl or people who give green cards…. So Dan breaks up with Blair because he does not want her to suffer.

The promo is not about the very next episode but the 3 next episodes IMO….

there was a spec a bit back (I don’t remember whose) about C&S walking in on DB just after they finished kissing, but before they had a chance to talk about what it meant. Dan makes up lame excuse and bails, CS buy it. That would give the Prince time to woo Blair with everything still up in the air with DB.
Source: becauseimalwaysright.tumblr.com