Between marriages, Moffat claims that he "shagged [his] way round television studios like a mechanical digger." According to an interview with The New York Times, Moffat met television producer Sue Vertue at the Edinburgh Television Festival in 1996. Vertue had been working for Tiger Aspect, a production company run by Peter Bennett-Jones. Bennett-Jones and his friend and former colleague Andre Ptaszynski, who had worked with Moffat on Joking Apart, told Moffat and Vertue that each fancied the other. A relationship blossomed and they left their respective production companies to join Hartswood Films, run by Beryl Vertue, Sue's mother. The couple have two children together: Joshua and Louis Oliver.  Before Moffat left Pola Jones for Hartswood, Ptaszynski produced Chalk, the series that the writer had pitched to him at the beginning of the decade. Set in a comprehensive school and starring David Bamber as manic deputy head Eric Slatt and Nicola Walker as Suzy Travis, the show was based on Moffat's three years as an English teacher. The studio audience responded so positively to the first series when it was taped that the BBC commissioned a second series before the first had aired. However, it was met less enthusiastically by critics upon transmission in February 1997, who had taken exception to the BBC's publicity department comparing the show to the highly respected Fawlty Towers. In an interview in the early 2000s, Moffat refuses to even name the series, joking that he might get attacked in the street.  After production wrapped on Chalk in 1997, Moffat announced to the cast that he was marrying Vertue. When she eventually asked him for a sitcom, he decided to base it around the evolution of their own relationship. Coupling was first broadcast on BBC2 in 2000, with his wife producing for Hartswood Films. The series proved to be highly successful, running until 2004 and producing four series and twenty-eight episodes, all written by Moffat. He also wrote the original, unbroadcast pilot episode for the U.S. version, also titled Coupling, although this was less successful and was cancelled after four episodes on the NBC network. Moffat has blamed its failure on an unprecedented level of network interference.

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