Question: What is the name of the man who had an affair with Sancha of Aragon?

Context paragraphs:
Sancha of Aragon: Sancha of Aragon (1478 in Gaeta – 1506 in Naples), or Sancia of Aragon, was an illegitimate daughter of King Alfonso II of Naples and his mistress Trogia Gazzela.  In 1494, she was married to Gioffre Borgia, youngest son of Pope Alexander VI.  Upon her marriage, she and her husband were created Prince and Princess of Squillace, a province in the south of Italy.  For the majority of their marriage, Sancha and her husband lived in the Vatican with the rest of his family.  There Sancha became friends with her sister-in-law Lucrezia, and allegedly had affairs with both of her husband's older brothers: Juan Borgia, 2nd Duke of Gandia, also known as Giovanni Borgia, and Cesare Borgia.  Her affair with Juan is sometimes said to be the reason for Cesare's alleged murder of Juan in 1497.

Andregoto Galíndez: Andregoto Galíndez (literally Lady Goth, daughter of Galindo, from Basque title "andre") was daughter of Count Galindo II Aznárez Count of Aragon by his second wife, Sancha Garcés of Pamplona.

Sancha of Castile, Queen of Aragon: Sancha of Castile (21 September 1154/5 – 9 November 1208) was the only surviving child of King Alfonso VII of Castile by his second wife, Richeza of Poland.  On January 18, 1174, she married King Alfonso II of Aragon at Zaragoza; they had at least eight children who survived into adulthood.

Alfonso II, Count of Provence: Alfonso II (1174 – February 1209) was the second son of Alfonso II of Aragon and Sancha of Castile.  His father transferred the County of Provence from his uncle Sancho to him in 1185.  Alfonso II was born in Barcelona.

Cantar de los Siete Infantes de Lara: The Cantar de los Siete Infantes de Lara (Song of the Seven Lara Princes) is a legend, perhaps derived from a lost "cantar de gesta", that relates a tale of family feuding and revenge, centering on the murder of the eponymous seven "infantes", princes, of Lara or Salas.  The legend survives in prose form in medieval chronicles, the oldest being in the extended version of the "Estoria de España" (History of Spain) compiles during the reign of Sancho IV of Castile, before 1289 (edited by Ramón Menéndez Pidal under the name "Primera Crónica General").  From the account found in this chronicle as well as mention in the "Crónica de 1344" ("Segunda Crónica General") and interpolations into a copy of the "Tercera Crónica General" dating from 1512, Menéndez Pidal found evidence for the existence of an ancient "cantar de gesta", lost but partially reconstructed, dating back to the year 1000, that would, along with the "Cantar de Mio Cid" and the "Poema de Fernán González", represent one of the most important epic "cantares" of Castilian literature, and the most primitive example of the Spanish epic.  The legendary tradition of the "Infantes de Lara" has also been developed though ballads.  Some more recent scholars have rejected this, dating the story to shortly before the surviving prose versions.  The "Infantes de Lara" were the children of Castilian nobleman Gonzalo Gustioz of Lara or Salas and his wife ""Doña Sancha"" (lady Sancha).  The story revolves around a family feud, an escalating tit-for-tat cycle of revenge, between their family and that of Sancha's brother, Ruy Velázquez and his wife "Doña" Lambra. <ref name="Barton137/8">Barton, pp. 137–138</ref>

Joan, Countess of Toulouse: Joan (1220 – Castle of Corneto near Siena, 25 August 1271), was Countess of Toulouse from 1249 until her death.  She was the only child of Raymond VII, Count of Toulouse by his first wife Sancha, daughter of King Alfonso II of Aragon.

Giovanni Borgia, 2nd Duke of Gandia: Giovanni Borgia, 2nd Duke of Gandía (1474 or 1476–1497) was the son of Pope Alexander VI a member of the House of Borgia who was murdered in 1497.  He was the brother of Cesare, Gioffre, and Lucrezia Borgia.  Giovanni, commonly known as Juan (or sometimes, Joan), is believed to be the eldest of the Pope's four children by Vannozza dei Cattanei, but this is disputed.  Due to the contents of a number of papal bulls issued after his murder, it is unclear whether Giovanni was born in 1476 or 1477.

Sancha of Aragon (died 1097): Sancha Ramírez (born 1045, died 1097) was an Aragonese princess, the daughter of King Ramiro I and Queen Ermesinda.  She was the Countess of Urgell from 1063 until 1065 as the wife of Count Ermengol III.  Her brothers Sancho Ramírez and García Ramírez became king of Aragon and bishop of Pamplona, respectively.  During her brother's reign she played an important role in consolidating the kingdom of Aragon, which had been founded by her father in 1035.

Monastery of Santa María de Sigena: Monasterio de Santa María de Sigena is a convent in Villanueva de Sigena, region of Aragon, Spain.  It was constructed between 1183 and 1208, founded by Queen Sancha of Castile, wife of Alfonso II of Aragon, for nuns from the richest families of Aragon.

Crown of Aragon: The Crown of Aragon ( ; Aragonese: "Corona d'Aragón" , Catalan: "Corona d'Aragó" , Spanish: "Corona de Aragón" ) was a composite monarchy, also nowadays referred to as a confederation of individual polities or kingdoms ruled by one king, with a personal and dynastic union of the Kingdom of Aragon and the County of Barcelona.  At the height of its power in the 14th and 15th centuries, the Crown of Aragon was a thalassocracy (a state with primarily maritime realms) controlling a large portion of present-day eastern Spain, parts of what is now southern France, and a Mediterranean "empire" which included the Balearic Islands, Sicily, Corsica, Sardinia, Malta, Southern Italy (from 1442) and parts of Greece (until 1388).  The component realms of the Crown were not united politically except at the level of the king, who ruled over each autonomous polity according to its own laws, raising funds under each tax structure, dealing separately with each "Corts" or "Cortes".  Put in contemporary terms, it has sometimes been considered that the different lands of the Crown of Aragon (mainly the Kingdom of Aragon, the Principality of Catalonia and the Kingdom of Valencia) functioned more as a confederation than as a single kingdom.  In this sense, the larger Crown of Aragon must not be confused with one of its constituent parts, the Kingdom of Aragon, from which it takes its name.

Supporting paragraphs: Sancha of Aragon Giovanni Borgia, 2nd Duke of Gandia
Answer: Giovanni Borgia