Edward is, at the moment, a man of simple tastes.  Good companionship, good drink, good food, and a good fight.  In that order.

He joined the Sea Dogs when he heard of Queen Elaine's plea for sailors and soldiers.

Why he joined and what his past is, he has kept close to the vest.  But his experiences in the Sea Dogs gave him a taste of a life he knew he wanted to keep tasting and often.