Damon compelled Caroline to rendez-vous amoureux, date him and she was only ever another one of his toys for blood, sex and maybe even because he was jealous of stefan and elena. He also abused her a lot and this is why Caroline hates Damon and hates him and elena being together. Hope this helped :)
Nothing she was his blood bag.she was a hommage to make Elena citron vert green jello and if he did than she would be with him not his best friend alarm and not his brother steathon Salvatore
