Why did Fredo betray Michael?

Could you elaborate on the reasons behind Fredo's betrayal of Michael? Was it due to personal jealousy or external pressures? Did Fredo feel unappreciated or undervalued in the family business? Perhaps there were underlying conflicts or unresolved issues that led to his ultimate decision? Understanding the motivations behind Fredo's actions would provide valuable insight into the complex dynamics of the Corleone family and the world of organized crime.