Ugh!! Pick any scene from 3x08, heh.
Um, I'd say the hallway scene in 3x08 when Jessi faces her subconscious knowledge that her mother was murdered - and Kyle was there by her side the whole time right up to the moment when her mother's heart stopped beating. What an intense scene. The way Kyle comforted Jessi without words by the end; the way they touched foreheads just melted me!
And a close second would be the scene when Kyle adores Jessi while she sleeps in the red dress!