Don't even bother breaking up, just start going out with other people. When she comes over one day and someone else is there she will get the message.

But I don't recommend being that way. I honestly don't understand how people can hate their ex. I don't hate any of my ex-girlfriends. If I still lived in the same town I’d probably still hang out with them. hell, one called my folks house just a few weeks ago. How can you love someone and then just hate them. I mean there are people I don't go out of my way for, but I don't hate them. I don't think most of them hate me either, I could be wrong but as far as I know I could still be friends with any of my ex girlfriends.