In Episode II, OBI-WAN GETS CAPTURED. His lightsaber is confiscated by the Separatists, and destroyed. He never recovers it. That lightsaber he lost was blue, by the way (which is interesting; he was more of the consular type, and Jedi consulars had green lightsabers). During the duel with Dooku, he was using a spare lightsaber given to him by the Jedi Order; the Order always had a buttload of spares in case someone’s lightsaber broke down or got lost.