Should we pay off our mortgage or put my inheritance in the bank?

I recently inherited a lump sum of money from my late grandmother. It's enough to pay off our mortgage with a small sum left over. My husband doesn't want to pay off our mortgage, he would rather invest the money, but I don't want to. I dislike being in debt, and it would be a relief to have everything completely paid off.

We are retired military and disabled vets. He is a software engineer, and I'm a registered dietitian. So we don't really need the income.

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