Just hoping isn't wrong.
You doing something so that they have to break up... that'd be wrong.
I have a friend whom I hoped would end it with his girlfriend but that was just because I think they were together just so they'd have someone to have sex with, there was no intellctual thing and they were always fighting which sucked ass when the rest of us tried to have a good time. They have broken up now and I think it's for the better.
So there are different reason why people should break up, just hoping isn't wrong and if they do break up, well why not just give it a go then...