How is jealousy breaking Gene apart?

I'm not so sure Gene was necessarily as jealous as he was paranoid. Gene liked and admired Finny, if he was jealous, it wasn't over Finny's intelligence or talent..... it was over Finny's complete self-assurance. Gene became suspicious, and yes, it was partly caused by jealousy, but more from fear that Finny was more intent upon sabotaging his own accomplishments than anything Finny actually did for himself.