Is my boyfriend being stupid?

Basically, I entered a writing competition not long ago, and my boyfriend has told me (after I'd entered) that if I won he didn't think he could be in a relationship with me because he didn't want "to live in my shadow" (that's quoted btw). He said what kind of a life was it when he'd wake up miserable everyday simply because I'd have something else to put on my UCAS application. Honestly, I don't really think I'd win anyway, I did it for the sake of doing it, but he thinks that leaving me is a fair thing to do (if I win), Is it me or is he being stupid? What should I do? He won't listen to reason.