Explain why Gawain savagely throws away the green girdle, and why does he put it on again. (Two separate questions.)

Gawain is disappointed in himself for violating the Chivalry code of honour, he failed to reveal the girdle to the Knight. Gawain sees no victory in this contest. He has forsaken honour and trust so he throws the girdle away to regain some honour. The girdle, however, is much too valuable to be thrown in the woods. It was after all a gift from his most worthy opponent. Gawain decides to reclaim it.