Get My Ex Back!

I can’t believe that my boyfriend did this to me. The other day he accused me of cheating on him with his boss from work. It’s a ridiculous thing to say, and I don’t know where he’s getting this idea, but he’s convinced. So of course he broke up with me. Now I need to know the steps to get my ex back and fast! I’ve heard that one of the things you want to do is to actually agree that the break up is a good idea, but that doesn’t make sense. Is this true?