I must have heard this song a million times. Early 60s music got played a lot in my house growing up. This song has always been a little sad. The man tells his partner to go out and have a good time at the dance, and he will be waiting for the last dance. The book says that this song was based on the true story of one of the songwriter's wedding. Doc Pomus had polio and could not dance, but his wife was a Broadway actress and dancer. She danced the whole night with others, but they went off together at the end of the night.
Musically, the lead vocal (Ben E. King) is poignant and wonderful, the upper harmonies are great, and the low bits are mostly solid. There is some poor quality in the lows, but I think that is likely to be the quality of recording equipment at the time. The rhythm is a slow Latin style beat. The book calls it Brazilian baion. Hutchinson encyclopedia points out the Phil Specter used it a lot in his work, and Wikipedia reminds us that Phil Specter was apprenticing with Lieber and Stoller while they were producing this song. Production is really strong on this song. Percussion, strings, guitars, harmonies, and nothing overrides the lead vocal. It all comes together perfectly.