Why Does Alfie Keep Betraying Tommy?

Changretta impatiently agreed to all Alfie's demands. ... Alfie revealed that he was suffering from skin cancer; he had intended for Tommy to discover his betrayal, track him down, and kill him so Alfie could die on his own terms, rather than the Mafia.

How did Alfie betray Tommy?

Things go well, but it is revealed that Hughes and the Economic League know of Tommy's plans. After some investigation, Tommy discovers that Alfie divulged the plans to Father Hughes, thereby betraying Tommy. During a confrontation, Michael Gray kills Alfie's associate, but Alfie talks Tommy out of killing him.

Why did Alfie betray Sabini?

Tommy tells Sabini at the Epsom Derby that it was because Sabini promised Alfie his bookies could work the derby but then changed his mind and didn't let his bookies work the event.