Why did the alliance break down between Brtain, USSR and the USA

Why did the Alliance break down in 1944 - 45? There were many aspects to the Alliance breaking down between 1944 and 1945 these are the long term hostility between the USA and the USSR, the arguments at the Yalta and Potsdam conference and the different personalities in the big and the change of leadership within USA and Britain. In 1917 civil war broke out in the USSR. The USA, Britain, France and the other countries decided to try and …

…did agree upon the final boarders of Poland although the USA and Britain disagreed. They also agree upon the reparations bill. The various disagreements the leaders had whenever they met was primarily to do with their very opposing attitudes. The primarily hates were between Stalin and Churchill, who were sworn enemies, while Stalin and Roosevelt were far more amiable when they met. This was mostly due to their ideological differences based on their respective governments.