Insurance

Even though I'm a native English speaker, I always assumed that people pronounce the word "insurance" like "in-SUR-ance". But my husband and some other people say "IN-surance" (ie, the stress is on the first syllable instead of the second).

I looked it up at Merriam-Webster and expected them to have just "my" pronunciation, but they have both! Check it out--they have audio samples of each.

So the question is: is there a "correct" way to pronounce it, and if not, then why are there two ways?