You should hire a bunch of guys to go on dates with her, and be complete jackasses... then you'll look awesome and all will seem well again =)......
Until one of the hired dates decides he loves your girlfriend, turns off the jackass, turns on the charm, and challenges your position as "The Boyfriend"! When it seems you are winning the game, he will drop the bomb and tell her all about the deal you made with him. He will apologize and give the classic "It started out as a job, but it's turned into so much more than that" line, and she'll buy it and leave you....
A few months down the road, after numerous attempts to show that you only did it out of misguided love and the best intentions, she'll see what kind of conniving jerk this guy really is and come crawling back to you =D
ok... it may not work in real life, but I claim rights to the movie
::EDIT:: Afterthought - After rereading it it seems kind of anti-climactic, but I'll work the kinks out and get back to you
--I'd rather be a could-be if I cannot be an are;--
-- because a could-be is a maybe who is reaching for a star.--
--I'd rather be a has-been than a might-have-been, by far;--
--for a might have-been has never been, but a has was once an are.--