Yea thats what I thought about too, Juliet resembling his ex wife. Also Kate has shattered his heart, and here's Juliet waiting in the wings. He may latch on to Juliet more than he normally would because of these captive circumstances and his need to not be alone or hurt by Kate. Everytime kate would try to talk to him about it, Jack would say "talk about what?" to avoid it. Juliet provides him with a focus to keep him from thinking about Kate.

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