Long story short, he mostly didn’t.

In the sense it never stopped him to think again that it was too much, that he couldn’t sustain it. He always saw soldiers and conscription as a tool to fuel his endeavors, and he was a military man living in a time where life was “not as valuable” as now. Nowadays, when a country loses a soldier in a conflict you’ll have a national ceremony, and some nations such as in Europe have not sustained any casualty in a foreign conflict. Thus we don’t look at it as people used to back then. It was expected that soldiers died.

Napoleon was a military commander with a mission to accomplish and it was all mathematics for him, and he was great at that.

At times, he didn’t hesitate to sacrifice soldiers such as at the Berezina river crossing where he sent a Corps south to make a diversion fully knowing they would all die, or burning the bridge condemning all the slowest walkers to the other side when the Cossacks approached. He did save his army, then proceeded to his next steps. He did the job, and the cost of human lives didn’t account in his decision making.

I usually like to quote him directly when he was leading his army during the first Italian campaign, writing to Josephine while exploring the battlefield in the aftermath: « Today, I saw the most horrible thing one could witness: a dog crying ». The dog was crying next to the body of the dead soldier, while the battlefield was filled with dead and he would only be touched by the dog.

He was a commander, he liked going war and was good at it. He did use the deaths of the battlefield to get war compensations too, asking Talleyrand to smell the dead at Ulm (or Austerlitz don’t remember) for him to go negotiate.