The Lobster Roll restaurant actually exists in Montauk, but is closed in the winter.

The role of Noah was written for Dominic West from the beginning, who originally turned it down.

Star Ruth Wilson shocked people when she abruptly quit the show before its final season in the summer of 2018. When reporters pressed her for an explanation, all she said was "It isn't about pay parity, and it wasn't about other jobs," Wilson told The New York Times. "I'm not really allowed to talk about it. There is a much bigger story." To get to the bottom of what happened, The Hollywood Reporter interviewed numerous insiders, and then it published the untold story of why Wilson left. The actress, who is restrained by an NDA, knew her role on the adult drama would involve showing some skin, but she felt the frequency and nature of her nude scenes were gratuitous. The production team was also reportedly sloppy about protecting actors' privacy on a number of occasions. "There sometimes were people there who didn't need to be, or the monitor was in plain view," an insider told THR. Another source alleged that a complaint was raised after a monitor was left on and someone not involved with the production was able to watch them shoot an on-location sex scene. Wilson finally negotiated her exit from The Affair after a shocking account of a drunken run-in with the show's executive producer and frequent director Jeffrey Reiner was published on the now-shuttered website Lenny Letter in 2016. Allegedly, Reiner crossed paths with Jenni Konner and Lena Dunham in the Hamptons and tried to persuade the Girls star to have dinner alone with Wilson, to convince her to "show her tits, or at least some vag" on his show. Then, Reiner allegedly pulled out his phone and showed off a photo of Maura Tierney, another star of The Affair, with a nude male actor's penis near her face. Evidently, it was meant to prove to Dunham the show had an equal male-to-female nudity ratio. Wilson raised a complaint with Showtime in early 2017 alleging The Affair was a "hostile work environment," and the network's parent company CBS opened an internal investigation sometime after. According to THR, the Reiner incident gave the actress the leverage she needed to negotiate her exit from the show. She reportedly received a substantial payout, shot all her scenes in the fourth season early, and refused to share a set with show runner Sarah Treem.

The series was co-created by Hagai Levi and Sarah Treem. However, Levi retired from writing the series during the second season. His stated reason was that the show was moving away from what he had envisioned. Treem was therefore "the best person" to author the show from that point on.

Ruth Wilson is frequently without clothes for her racy sex scenes with Dominic West in this series. In an interview with Edit magazine, Wilson both defended and critiqued the use of females getting naked on the show: "I argue this stuff all the time; that these scenes need to be real and they need to have a narrative as much as any other scene. They can't be purely titillation. They need to move the story forward and the characters forward." Wilson isn't opposed to appearing naked on film, but she won't do it just because it's asked of her: "I have a big concern about how women are treated in the industry generally, and how they have to provide the titillation because penises can't be seen on screen but breasts can. It's assumed that women will get their breasts out, and have to get their breasts out, and I balk at that. It's unnecessary and it's unfair." For Wilson, her role on The Affair can be a double-edged sword, but she is intent on asserting her authority over her naked scenes.

Both actors playing Alison and Noah are UK born.

Dominic West and John Doman also worked together in "The Wire", as opponent characters.

In the first episode Noah tries to guess what Alison's favorite book was. He incorrectly guessed "Anna Karenina". Alison (Ruth Wilson) was actually in the the movie "Anna Karenina".

The book pages in the intro are from the novel "Contact" by Carl Sagan.

At one point someone offers Noah a drink, saying, "Jameson ok?" Dominic West's character in The Wire only drank Jameson Irish Whiskey.

The last names of Cole and Alison is Lockhart. That is also the same last name of Maura Tierney's character on "ER," Abby Lockhart.

Abigail Dylan Harrison replaced Leya Catlett as Stacey Solloway, Noah and Helen Solloway's youngest daughter, in season 3.

At the onset of the series The Affair (2014) it is safe to assume that Ruth Wilson as Alison Bailey and Dominic West as Noah Solloway will be having an affair which will be the central plot of the story. In the series Luther (2010) Ruth Wilson as Alice Morgan plays the foil of D.I. John Luther portrayed by Idris Elba. Idris Elba was the key antagonist Russell "Stringer" Bell, who was pursued by Dominic West as 'Det. James 'Jimmy' McNulty' in the HBO series The Wire (2002).

Deirdre O'Connell and Peter Friedman both have recurring roles on Hulu's "The Path".

In Season 2, Maura Tierney's character had an affair with the character played by Josh Stamberg, who also played a character who had an affair with Lauren Graham's character on Parenthood. Lauren Graham replaced Maura Tierney on Parenthood after she left the show due to her breast cancer diagnosis.