Gawyn was ever unwilling to settle on a course. If he'd just decided to join Elaida because Siuan was foolishly risking Elayne's life and to get revenge against the Dragon Reborn for murdering his mother and conquering his country, then at least I could respect him for being faithful to his cause. But the truth is, he was never that. I probably should have seen it from the beginning, what with him letting Siuan go and betraying his cause for Egwene, or his absence from the Succession War storyline, but the later books have made it bloody obvious.
He betrays his cause and his Younglings because he doesn't feel he belongs there anymore and goes of to join the Rebel Aes Sedai, then he feels he shouldn't be following their orders and goes off to save Egwene, then he decides serving Egwene isn't everything he always wanted so he runs back home to Andor - after Elayne has already resolved the crisis there - then figures 'no wait, maybe my place is with Egwene after all!' for a while before deciding, no, his place is martyring himself to kill Demandred!
Gawyn is all rash decisions and no commitment, and this is something that comes to be most obvious in the latest books.
~Master Splinter
Victorious in Bergioyn's legendary 'Reverse Mafia'. *MySmiley*