There's Something About Sally - S1.E19

Kurt is hanging out with Sally's ex, Kevin under the premise it's all right for him to do this because Kevin was his friend before he dated Sally, even though Sally is still not over him, and Brooke & Chris had advised him it was a bad idea because Kevin broke Sally's heart. Sally finds out that Kurt is still friends with Kevin when she goes round to Kevin's to collect some of her stuff & finds Kurt hiding in the bath. Kurt tries to stop Sally hating Kevin by getting them to talk to each other, and he unwittingly gets Sally back together with Kevin.