In my history class, we were taught that Hitler wanted to fight with Russia against the Allies but Hitler even said that the greatest threats to Europe were Jewry and Bolshevism. Surely fighting with the Read Army would promote the spread of communism in Western Europe and then Hitler would have an even bigger issue after the war, presuming that he won. Could it just be that Hitler was deluded or am I missing something?
I question what you were taught. Hitler had nothing but contempt for communism and Slavs, and this was well documented even before he became Chancellor. The Molotov-Ribbentrop Agreement was nothing more than strategic positioning by both sides, as the USSR actually tried to make a deal with France and the UK against the Nazis beforehand, but was ignored. It is however known that he had admiration for the British Empire. Is there a particular source that was used as the basis for this claim?
Firstly, Hitler and his generals knew from the first war that fighting on two fronts is not ideal.
Secondly, by the Spring on 39, war was already looking likely. Stalin was aware that the Soviet Union was not ready for a long, drawn out fight and looked to make a pact with Britain but British politicians refused as they were not exactly a fan of Stalin or Communism. Stalin then looked to make a pact with France and again their politicians refused as it may have been seen to give endorsement to the French Communist party and weaken the French political elites.
Stalin was then forced to make a pact with Hitler in a effort to prevent war with Germany. The Soviet Union at this time was already engaged in conflicts with Japan and didn't want themselves to fight on a second front.
Although Hitler didn't believe that Britain and France would declare war over the invasion of Poland, the Molotov-Ribbentrop Pact was designed to give him a free hand in taking parts of Poland that were vital for the German economy and part of his larger ambitions and needs.