A traveller pulls into a hotel around midnight and asks the clerk for a single room.

A traveller 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 gorgeous 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 $3000. What's the meaning of this? he yells at the clerk. I've only been here one night! Yes, says the clerk, but your wife has been here for three weeks.