Your husband is an insulin dependent diabetic and an opiate addict. That combo is apt to result in something out of the ordinary when it comes to the odor of his output.
Are you now reliving every moment of the last few years, looking for the signs you may have missed along the way. Been there/done that, too. You will make yourself crazy with this stuff.
What can you do, in the here and now, to take the primary focus of your life off his addiction and refocus on you and your two wonderful children?