You seem to be confused about what you want to buy.
You can buy life insurance from a life insurance company for a modest monthly premium, and this replaces the life cover you used to get with your job. That gives a lump sum to your estate in the unlikely event of your death and this could be used by your husband to pay off the mortgage.
However that is not income protection insurance, which your husband could also purchase, in the event of loss of his earnings through redundancy (say). Personally I don't think they are worth the money (unless your husband knows he is in an industry/job that is at risk). His credit rating doesn't really come into it