You know someone is completely done with you. In a sense that they've gotten everything they can out of you and in uninterested in you anymore. Its like you never existed at all. They never really wanted you because they always had something better than you. You was just something they could get off on until the time came for them to finally get rid of you. Of course it doesn't matter how you feel for them because they deal with it everyday. Constantly letting people down or perhaps getting their hopes up for completely nothing.
It really sucks because its like you can't even at least be friends with this person anymore. They've move so far along and has forgotten about you that you've become that insignificant to them.