Gossip Girl Spoilers: Trouble ahead for one of the GG couples!

Kristin dos Santos of E! Online tells us that there may be trouble ahead for one of our Gossip Girl couples.. read ahead for the spoilers on which couple it is!

Drew in Walhalla, S.C.: I'm a freak for Chuck and Blair on Gossip Girl! Tell me they aren't going to break up any time soon.
They aren't. It's actually Rufus and Lily's relationship that will be in a very bad place until the end of the season. From what I understand, it all stems from a letter that Serena's father is going to send her. And of course, it doesn't help that Bart Bass is back in the mix!

Source: Watch with Kristin