'Gossip Girl': The Many Men of Serena van der Woodsen
Season 3Though Carter (Sebastian Stan) had been around since Season 1, his romantic relationship with Serena didn't begin until Season 3. In the third season premiere, it was revealed the two spent their summer together looking for her father. Their relationship ends when she finds out he left Bree Buckley's cousin at the altar. Though she tries to rekindle their relationship by freeing him from his past, things are done for good when she finds out he knew where her father was all along.
Source: GIOVANNI RUFINO/Warner Bros.