So what if Philip dosen't get dysentery, and stays with the Crusade?Wikipedia said:By the time Acre surrendered on July 12, Philip was severely ill with dysentery and had little more interest in further crusading. He decided to return to France, a decision that displeased King Richard I, who said, "It is a shame and a disgrace on my lord if he goes away without having finished the business that brought him hither. But still, if he finds himself in bad health, or is afraid lest he should die here, his will be done." So on July 31, 1191 the French army of 10,000 men (along with 5,000 silver marks to pay the soldiers) remained in Outremer under the command of Hugh III, duke of Burgundy. Philip and his cousin Peter of Courtenay, count of Nevers, made their way to Genoa and from there returned to France. This decision to return was also fuelled by the realization that with Richard campaigning in the Holy Land, English possessions in northern France (Normandy) would be open for attack. After Richard's delayed return home after the Third Crusade, war between England and France would ensue over possession of English-controlled territories in modern-day France.
So what if Philip dosen't get dysentery, and stays with the Crusade?
http://en.wikipedia.org/wiki/Third_crusade said:During the winter of 1190-91, there were further outbreaks of dysentery and fever, which claimed the lives of Frederick of Swabia, Patriarch Heraclius of Jerusalem, and Theobald V of Blois. When the sailing season began again in spring 1191, Leopold V of Austria arrived and took command of what remained of the imperial forces. Philip of France arrived with his troops from Sicily in May.
Richard arrived at Acre on June 8, 1191 and immediately began supervising the construction of siege weapons to assault the city. The city was captured on July 12.
Richard, Philip, and Leopold quarrelled over the spoils of their victory. Richard cast down the German standard from the city, slighting Leopold. Also, in the struggle for the kingship of Jerusalem, Richard supported Guy, while Philip and Leopold supported Conrad, who was related to them both. It was decided that Guy would continue to rule, but that Conrad would receive the crown upon his death.
Frustrated with Richard (and in Philip's case, in poor health), Philip and Leopold took their armies and left the Holy Land in August. Philip left 10,000 French crusaders in the Holy Land and 5,000 silver marks to pay them.
As for them hating each other, i think that was only after the Crusade. After all, Philip helped Richard get his throne.
Richard was engaged to Philip's sister (i think wiki said half-sister), and broke it off for Berengaria.I don't really know, all I heard about the subjects that they used to be friends when growing up and then got into bad arguement about a woman. I heard from my quite proficient history teacher, but well it does not seem that trustworthy information.