'serial affairs' is correct and usable in written English.
It is used to describe a pattern of engaging in multiple romantic or sexual relationships over a period of time. For example, "John had a long-standing history of serial affairs, often overlapping in time."
Not a few have serial affairs or marriages.
Life keeps letting Dobbs down: his adored wife (Harriet Andersson) has serial affairs, his work has lost its honor.
He admitted to being humbled and ashamed of behavior that first came to light in November 2009 with revelations of his serial affairs.
This, however, takes the form of serial affairs (another illusion) until he meets the glance of Leila passing by and believes himself to be in love.
It was a French film about three non-specifically unhappy couples who had serial affairs with one another and a troop of third and fourth parties, against a rainy Parisian backdrop that looked as if it had been shot through a translucent beach ball.
Don Draper, one of the main characters, eventually realized that serial affairs and client victories were hollow and short-lived.
Equally concealed were his serial infidelities, his affairs with women ranging from 19-year-old interns to Marilyn Monroe – a record of womanising inside the White House that makes Bill Clinton look like a boy scout.
By this time it is evident that Abigail is both a product of George's fecklessness (those serial and simultaneous affairs, that easy betrayal of Sean) and a reaction against it (her hardworking career and above all her tenacious attachment to Fortune Street).
One came from a man who is either a serial liar, a foreign affairs ignoramus, or a terminal victim of historical amnesia.
Whether he's writing about a serial killer, a love affair between a doctor and poet in Martha's Vineyard or a middle-aged ad executive who miraculously becomes an exceptional putter and joins the senior golf tour, his books are accessible and engaging.
Noted for his diverse roles, Fiennes later portrayed a novelist in the film The End of the Affair (1999), a serial killer in Red Dragon (2002), and a widower determined to find his wife's killer in The Constant Gardener (2005).
