There is no limit on how many life insurance policies you can buy, but there is a limit on how much total life insurance your husband can have, typically it's a multiple of his annual income. Sometimes the limit may be as high as 20 times his annual income, or more.
Also, you husband will need to sign paperwork to allow the life insurance to be taken out on him, you can not do it without his consent.
He may need to answer some health questions, and maybe take a physical exam if required by the life insurance company.
The physical examination is paid for and set up by the life insurance company.
Here's an article that provides more information explaining how many life insurance policies you can have.