There are a lot of slams in the comments about how this film is not politically correct, or downright misogynistic. True enough, I suppose, but it isn't fair to apply today's standards to a film that is over forty years old. I was a child at that time, but a man's home really was his castle then, and yes that was definitely to the detriment of the women. But that is the way it was. So get over it. The film is a lot of fun if you don't wear the ideological blinders when you watch it. Walter Matthau is always fun to watch, and Inger Stevens was, of course, serious eye candy. There are a lot of other pretty girls in the film, and Robert Morse's character was a hoot, seeing him rationalize his lust into caring so much for his wife that he must protect HER from knowledge of his adultery. The cameo vignettes were mostly amusing as well. It is light comedy, so don't expect to roll on the floor, but I say, check it out.
Review of A Guide for the Married Man
