There are many natural products that will enhance your husband's sex drive without the side effects!
Your husband isn't deficient in v1agra - it is dangerous. Simply for it's tie to heart problems and the fact that it is not known if it will have long term detrimental effects.
Please look into a natural alternative before you succumb to a pharmaceutical.
How long has this been going on? Sometimes due to stress and life's ups and downs the sex life can be directly effected. Please feel confident in yourself and keep doing what you are doing, it will get better.