Could you be thinking of Ten Thousand Bedrooms (1963)? It starred Dean Martin but not Frank Sinatra, too.
Plot: Dino plays Ray Hunter, a Conrad Hiltonesque playboy hotelier at large in Rome.
Starring: Dean Martin, Anna Maria Alberghetti, Eva Bartok, Dewey Martin, Walter Slezak
Check this list of movies: http://www.deanmartinfancenter.com/index/rightframe/08moviesb/MOVIEb.html
Are you sure the movie starred both actors?
Maybe it was "Some Came Running" (1958) but the plot doesn't fit: Sinatra is a WWII veteran who goes back to his home town after trying his luck and failing as a writer.
EDIT: Who's Been Sleeping in My Bed? (1963) may be a better fit to your description but, again, it doesn't co-star Sinatra.
Actor Jason Steele (Dino) plays a caring, godlike doctor on television. Off the set, he's the insecure fiancee of Melissa, a pretty art teacher. Jason doesn't know what to expect of marriage, especially after seeing how the fires have burned out in all of poker buddies' marriages. Complicating matters is that his friends' wives have confused Jason with his television persona and they keep popping up at his house ready to see what his bedside manner is like.
· 9 years ago