After Michael and Kay are dancing in the communion party, we see Fabrizio ("Fred Vincent"), leaving his pizzeria in Buffalo, New York, and starting his car, at which point a previously planted car bomb explodes.He stumbles out of the car, then dies. This was Michael's vengeance upon Fabrizio for killing Apollonia.
It's revealed Fabrizio owned Fred's Pizza, having changed his name to Fred Vincent. Naturally, Michael orders him killed and in a suitably ironic fashion, Fabrizio dies a car bomb like Apollonia.
For the most basic reason of all: Money. Barzini, through his sources, had managed to locate Michael (as Don Tomasino had deduced) and managed to turn Fabrizio. But Fabrizio didn't mean to kill Apollonia.
Michael has become a true Corleone (embracing both Italian culture and mob affiliation), and his marriage to Apollonia signifies Michael's official acceptance of this change and what it means for his future. When Michael marries Apollonia, he is wedding himself not just to her, but to Sicily and his father's values.
Toward the end of the film, Michael names Vincent as his successor, on condition that he break off his relationship with Mary. After her brother's debut concert, the assassin Mosca tries to kill Michael. One bullet grazes Michael's shoulder, but the other accidentally hits Mary in the chest, fatally wounding her.
In Winegardner's 2006 sequel, The Godfather's Revenge, Fredo appears in one of Michael's dreams. In the dream, Fredo warns Michael about an unspecified threat, and asks him why he had his own brother killed. Much of the novel portrays Michael dealing with his guilt over Fredo's murder.
Tragically, she's later killed in a car bomb planted by Michael's bodyguard Fabrizio (Angelo Infanti), who betrayed him to his enemies. While Michael gets revenge on those who ordered the hit, Fabrizio is never seen again.
The Godfather's Michael Corleone may have loved many things, but his first wife Apollonia wasn't one of them. The pair were wed in Sicily in the mid-stages of the groundbreaking 1972 Francis Ford Coppola film, not long after Michael took refuge there after murdering police captain McCluskey and Virgil Sollozzo.
Kay did not know. In the Movie, Michael tracks Kay down after he has been back for several years. In the movie Kay does not know. In the book Kay does not know.
Due to Michael's marriage to Apollonia taking place entirely in Sicily, Kay is apparently unaware that Michael was a widower when he returned to America. She did, however, notice that he was somewhat rougher in bed when they had sex. Kay eventually had two children with Michael, Anthony and Mary.
Puzo characterizes Carlo as "a punk sore at the world", and his angry behavior is exacerbated by the Corleone family shunting him aside after marrying into the family. He physically abuses and cheats on Connie.
Fabrizio had long wanted to leave Sicily and go to America in order to live a better life. Following Michael's wedding he was soon bought out by Don Emilio Barzini who at the time was in a bloody war with the Corleone Family and wanted to kill Michael Corleone.
Mario Puzo's original novel and the film imply Tessio's death, but Mark Winegardner's sequel novel The Godfather Returns explains that he is executed with a gunshot at point blank range by his enforcer Nick Geraci.
Al Neri informed Michael during the confirmation party for his son Anthony, that Fabrizio now owned a pizzeria in Buffalo under the name 'Fred Vincent'. Michael sent men to track him down, and Fabrizio was killed by a car bomb set by Neri, thus avenging Apollonia.
There's a scene in "Godfather II" where Vito Corleone is in his dimly lit apartment worried about his son Fredo. Fredo has pneumonia and is being tended to by his mother and a nursemaid using a glass tumbler with a flame underneath. The thought was it would suck the illness out of his tiny body.
Originally Answered: In The Godfather (1972 film), what would happen if Apollonia was not killed and returned to America with Michael as his wife? Michael would have had a much more peaceful home life. A Sicilian woman would have been well informed on how to keep her nose out of her husband's business.
Michael and Kay tour Sicily together, during which Michael asks for Kay's forgiveness. Kay admits she will always love him, and they begin to rekindle their relationship.
By The Godfather Part II, Kay has decided that Michael is a cold, distant, inattentive husband and father, but only after an attempt is made on his life in the family home does she resolve to rebel against him. At first, Kay's rebellion is silent and private: she aborts the child she is carrying.
Al Pacino said that Michael loved Kay from the beginning. Remember that Mario's character of Michael was a man who had dreams and I do not ever want to dismiss this important deep aspect of Michael.
The marriage, however, has made Michael's presence there known to the Corleone Family's enemies. Necessary precaution restricts the couple inside the villa's walls, but Michael relishes his days as a newlywed and spends the time teaching Apollonia English and instructing her to drive a car.
After Sonny's death, Don Corleone agrees to lend his political protection to the enterprise and forgive the other families for having his son killed. Although it initially appears that Don Philip Tattaglia is responsible for organizing the anti-Corleone alliance, Vito soon realizes that Barzini is the true mastermind.
Vito warns Michael that Barzini will set Michael up to be killed under the guise of a meeting; Barzini will use one of the Corleone family's most trusted members as an intermediary. Shortly afterwards, on July 29, 1955, Vito dies of a heart attack in his garden while playing with his grandson, Michael's son Anthony.
Devastated by the loss, Michael retired to Sicily and lived in Don Tommasino's old villa, where he once lived with his first wife Apollonia. He died there in 1997, distraught and alone, of a stroke while sitting in a chair in front of the villa.
It's also worth remembering that Kay was actually Michael's second wife and that there's nothing to suggest that he cheated on either Apollonia or Kay post-marriage but, technically, he was "involved" with Kay when he married Apollonia.
