Occasional Wife

Occasional Wife was a half-hour American sitcom that aired on NBC on September 13, 1966, and ran until May 9, 1967.

The lead character was Peter Christopher, a bachelor who enjoyed the single life but was blocked from professional advancement by not having a wife. Peter's boss, baby-food manufacturer Max Brahms was, because of his product, a strong believer in marriage and family. Christopher asked a young painter, Greta Patterson, to pose as his wife at company functions. In return, Peter set up Greta in an apartment above his own in a Manhattan building. Greta would use the fire escape to slip in to Peter's 6th floor apartment from her apartment on the 8th floor whenever his boss would drop by unexpectedly. As a silent running gag, Brian O'Byrne played the "Man in the middle" who bemusedly watching the comings and goings of the two from his 7th floor vantage point. The sitcom's uncredited narrator was the well-known sports announcer Vin Scully.

The series first experienced good ratings, tying at #18 with The Man from U.N.C.L.E. in the Nielsen ratings. The series then fell to #64 in the ratings after having to compete against ABC's popular series The Invaders and the CBS staple The Red Skelton Show. Occasional Wife was canceled after one season.
From: Wikipedia.org

Linked from nostalgia and retrospection posts:

• CLASSIC TV — O
• 1966 TV Guide Covers