"Three Weeks" joke

A tourist pulls into a hotel around midnight and asks the clerk for a single room. As the clerk fills out the paperwork, the man looks around and sees a attractive blonde sitting in the lobby.

He tells the clerk to wait while he disappears into the lobby. After a minute he comes back, with the girl on his arm.

"Fancy meeting my wife here," he says to the clerk.

"Guess I'll need a double room for the night.

"Next morning, he comes to settle his bill, and finds the amount to be over $5000.

"Whats the meaning of this?" he yells at the clerk. "I have only been here one night!"

"Yes," says the clerk, "but your wife has been here for three weeks."