Infidelity

 is the 2nd episode of the fourth series of Men Behaving Badly, which was broadcast on 1 June 1995.

Summary
The episode begins with Tony and Deborah sitting watching a drama programme, in which Deborah is engrossed while Tony is finding it tediously boring. After he fails to divert Deborah's attention away from the TV and onto himself, she loses patience and firmly states that although she finds him attractive, Tony's selfishness and immaturity will always prevent them being a couple.

Gary meanwhile is starting to grow suspicions that Dorothy could be having an affair after reading an article in a magazine that bears striking resemblance to the couple's relationship (such as receiving guilt inspired presents and giving lame excuses to avoid seeing each other). The evidence prompts Gary to ask Dorothy outright upon her arrival at the flat, to which she simply replies 'that its for you to find out'.

Gary decides to play detective in order to find out Dorothy's whereabouts and begins by hiring a disguise (a Mexican hat) and a red Nissan Micra which he sits in outside Dorothy's parents' house to keep watch on any suspicious visitors. Tony meanwhile joins the Happy Companion Scheme at the local old people's home, in the hope that it will prove to Deborah that he is capable of caring about people other than himself.