Marriage Italian Style

Marriage Italian Style ( ) is a 1964 Italian film directed by Vittorio De Sica and starring Sophia Loren, Marcello Mastroianni, and Vito Moricone.
The film was adapted by Leonardo Benvenuti, Renato Castellani, Piero De Bernardi and Tonino Guerra from the play "Filumena Marturano "by Eduardo De Filippo. 
"Filumena Marturano" previously was adapted as a film in 1950 in Argentina.
Plot.
It tells the World War II era story of a cynical, successful 28 years old businessman named Domenico (Marcello Mastroianni), who, after meeting a naive 17 year old country girl, Filumena (Sophia Loren), one night in a Neapolitan brothel during bombing outside , keeps frequenting her for years in an on-again, off-again relationship spanning 22 years. From the very beginning, Filumena is deeply in love with Domenico but her love is not reciprocated. After Filumena expresses her wish to be solely his woman, Domenico arranges a lease for her with Rosalie as maid and Alfredo(Aldo Puglisi) as the butler and arranges a job for her in his shop. He eventually takes her in his house as a semi-official mistress under the pretense that she is the niece of Carmela (his mother's old maid) to take care of his ailing, senile mother. Domenico's mindset about Filumena's past keeps him from taking their relationship seriously. 
After having fallen for the young 20 year old cashier of his store; Domenico, now 50, plans to marry her. But he finds himself cornered when Filumena feigns illness and "on her deathbed", asks to be married to him. Thinking she'll be dead in a matter of hours and the 'marriage' won't even be registered, he agrees. After having been proclaimed his legal bride, the shrewd and resourceful Filumena drops the charade of feigning death. This puts Domenico in a fit of rage as he feels that Filumena tricked him for the money. But Filumena reveals the real reason for the marriage: she did it for her 3 children that she bore(Umberto, Riccardo and Michele) . As the children were coming of age, she wanted them to have a family name,precisely, Soriano. 
Domenico won't accept this and decides to contest the marriage. The law comes in his favour and the marriage is annulled. Filumena accepts the annulment but tells Domenico that he fathered one of the children. She does not say which as she considers all of them as equal.However, she gives him a hint that his child was conceived on the night Domenico said " to pretend they are in love" and gave her a 100 lire note where she wrote the date of that night. She leaves that note to Domenico. Domenico is visibly rattled by this revelation but can't solve the clue. 
Domenico tries desperately to figure out which child he fathered. He visits the children at their workplace and tries other means but hits a dead end. 
He meets up with Filumena and tries to force an answer out of her but she reveals nothing more. As a last resort, Domenico decides to confront the children directly but Filumena vehemently opposes this as it would wedge a barrier between the children due to the prospect of Domenico's money. As both of them scuffle, they tumble down and fall into each other's arms. The couple then proclaim their love for each other with a kiss and decides to remarry. 
At the church, the boys wait, and Domenico arrives. Domenico mentions that, because he will be marrying their mother, he will give them his name. However, he continues to prod them for clues but again comes out with nothing as they all share some resembling traits. Filumena rushes in, and Domenico smiling with joy, tells her how wonderful she looks and the marriage takes place. 
Back at home, the sons bid their mother goodnight. As the boys, one after another say goodnight to their 'father' Domenico, he smiles broadly at this and says that he will see them tomorrow.
Filumena sits and weeps with joy at this. When Domenico asks why she is crying, she states it feels wonderful to cry.
Reception and Awards.
The film was received favorably. The "New York Times" noted that it was the fourth quality collaboration between director Vittorio De Sica and Sophia Loren, and the second to include Marcello Mastroianni in the mix, the "warmup" for this movie having been 1963's "Yesterday, Today and Tomorrow". The review described it as a "wonderfully flamboyant" film, and provided some context for the film, noting that Naples (at least in 1964) was "a quite unusual place, where the people are highly individual and may have bizarre relationships."
It was the second highest-grossing Italian film in Italy for the year, behind "A Fistful of Dollars", with a gross of $3,725,000.
The film was nominated for Academy Awards for Best Foreign Language Film in 1965 and Loren for Best Actress in a Leading Role in 1964. It was also entered into the 4th Moscow International Film Festival.