Serial Spouse

Some people just can't seem to make it work. They go through divorce after divorce and never seem to learn their lesson. These characters are typically middle-aged, otherwise successful men, but none of these are requirements. The only requirement is that the character has been through at least two divorces.

There are numerous reasons for a character's marriages to repeatedly fail. Sometimes a needy best friend drives a wedge. Sometimes the character is still to devoted to a lost loved one. Usually, it's because they're simply Married to the Job.

This trope is often part of a character's Dark and Troubled Past, but it can also be played up for comedy. In both comedies and dramas, the character is often part of a Dysfunction Junction.

Bare in mind that a marriage doesn't necessarily constitute a divorce. If the character has been married twice, but one of the marriages ended in death, it doesn't count.

Examples of Serial Spouse include:

Anime and Manga

Big Mom from the Whole Cake Island Arc on One Piece. She has had 43 husbands, and tends to get rid of each after bearing his children. Only one of her ex-husbands - Pound - has actually appeared in an episode, unless Kaito was also one of them, something that is heavily implied but never confirmed. Many of them were not human.

Film

In the film version of Jurassic Park, Ian Malcolm comments at one point that he's always looking for the next Mrs Malcolm. It's implied that all of his marriages ended in divorce.
The movie The Marrying Man centered on a couple who married each other and then divorced multiple times over the span of decades. By the end of the movie they are about to get married for the fourth time.
In The Heartbreak Kid, Ben Stiller character Eddie rushes into marriage with Lila. During the honeymoon, he realizes how mismatched they are and meets another woman Miranda. After many mishaps, both women leave him. Years later, he is settled in Mexico, and Miranda visits him. In the final scene he makes plans to go on a date with her and after she leaves, it is revealed that he is married to a third woman, and possibly is going to divorce her to be with the One.

Live Action TV

Wilson on House had been divorced twice at the start of the show. He went through his third divorce in season two.
Gibbs on NCIS has three ex-wives, though he has actually been married four times.
On Criminal Minds, Rossi has been divorced three times.
On Castle, the titular character has two ex-wives.
On Law & Order, Jack McCoy has been divorced twice. Lennie Briscoe also has multiple ex-wives, although the exact number is unknown.
Guinan on Star Trek: The Next Generation has been married 23 times. It's not clear if all these marriages ended in divorce, or if she outlived some or most of her husbands. Seeing as she's over 500 years old and her species is rarely found in large groups, the latter is likely.
Ross on Friends had three ex-wives by the end of the series.

Ross: I'm gonna go out on a limb here, but No Divorces in '99!
Monica: Aren't you still married to Emily?
Ross: Just The One Divorce in '99!

John Munch from Homicide: Life on the Street and Law and Order Special Victims Unit had two ex-wives in his past, married a bartender in Homicide's last season, and had divorced her by the finale movie. There was a reason he always got teamed with Briscoe during crossovers.
Ron Swanson on Parks and Recreation has two ex-wives named Tammy, which is also his mother's name.
On Community, Pierce has been divorced seven times.
Al Calavicci of Quantum Leap had five wives, three of which are confirmed to have left him in a divorce (or divorce-like circumstances), and one is implied to. Only the first one really "worked": She only left him because she waited long enough after he was declared dead.

Theater

Tanya from Mamma Mia!
Millionairess Claire Zachanassian in Friedrich Dürrenmatt's play The Visit. Over the course the play, she divorces her seventh husband, marries and divorces the eighth, and prepares to marry the ninth.

Western Animation

One of Marge's sisters on The Simpsons: Selma Bouvier-Terwilliger-Hutz-McClure-Anderson-Simpson-D'Amico. She refused to have a Citizenship Marriage with Apu Nahasapeemapetilon just because his name is too long.

My name's already Selma Bouvier-Terwilliger-Hutz-McClure. God knows it's long enough without Nahassapeema-whatever.

Krusty is worse. At last count, he had been married fifteen times. Many fans believe the reason he has so many merchandising deals is because of all the alimony he has to pay.

In Family Guy, Lois' sister, Carol has been divorced nine times. She's currently married to Mayor Adam West.

Real Life

Elizabeth Taylor was married eight times, including twice to Richard Burton. One of those marriages ended when her husband died but all the other ones ended in divorce.
Larry King was married eight times, to seven different women. All but the last marriage ended in divorce.
At the time of her death, Zsa Zsa Gabor was living with her ninth husband. All of her previous marriages ended in divorce, except one that was annulled.
Mickey Rooney was married eight times and divorced seven times. At the time of his death in 2014 he had been living with his eighth wife for thirty-six years, which is more than the length of all of his previous marriages combined.
Henry VIII of England is probably the... er, king of this trope. He created an entire church (with him as the boss) in order to get his marriage annulled. He married six times in total; two of his marriages were annulled, three ended in the wife's death (twice with a bit of help from Henry), and the last ended with Henry's death.