Ruby is your triplet sister, it was Aquamarine, Ruby, and Jadeite. She knew that Aqua had also been reincarnated but didn't know you (Jadeite) had been reincarnated as well, thus making Aqua and Ruby closer and sort of neglecting you. Both she and he still talk to you, but not as much as they talk with each other, leaving you to do your own thing and him not caring. She still cares for you, but maybe not as much as Aqua. You weren't in on their secret anyway, so why should you matter more?