Double-Minded …

… one who is divided in his interests or loyalties, wavering, uncertain, two-faced, half-hearted.

Double Agent…
… a spy who works for two mutually antagonistic countries - (military) a secret agent hired by a state to obtain information about its enemies or by a business to obtain industrial secrets from competitors

Traitor …
… one who betrays another’s trust

Judas…
… One who betrays another under the guise of friendship.

“The enemy of my enemy is my friend …”

To the one who said that … you have been discovered. Too sad this is the legacy you have chosen to leave. You sold your soul, and you did it for naught. Your pearls of wisdom have turned out to be nothing more than meaningless drivel.