Another joke : you will laugh when you understand (Jakarta)

After directory assistance gave me my boyfriend's new telephone number, I dialed him and got a woman.
"Is Robert there?" I asked. "He's in the shower," she responded.
"Please tell him his girlfriend called," I said and hung up.
When he didn't return the call, I dialed again. This time a man answered. "This is Robert," he said.
"You're not my boyfriend!" I exclaimed.
"I know," he replied. "That's what I've been trying to tell my wife for the past half-hour."