LOTR: FotR Question..?

Frodo and Sam left on their own because their own fellowship members started to turn on Frodo because they wanted the ring. Specifically Boromir and Aragorn. Boromir was was about to kill Frodo, but Frodo put the ring on so he could dissappear and escape. Aragorn then started after Frodo for the ring, but soon realized that he was being corrupted by the ring. This is why Frodo had to leave because the ring was corrupting the fellowship. Aragorn understood this.