Your husband’s insecurity is likely at the root. I doubt there is anything that you can do that you haven’t already done to ensure your commitment. It is also very likely that his dragging up this issue on a regular basis is his way of preventing a more intimate connection with you. By pulling this issue out of the bag he can keep himself from being fully committed to you.
I would set a very strong boundary about this type of emotional abuse from him. Explain that you won’t tolerate it as it isn’t what you signed up for when you came back, and that if he can’t quit on his own you want to go to couple therapy with him to let a professional help.
This sort of thing tends to come from very insecure men who have jealousy issues that put all of the responsibility on their partner. It is a way of them not dealing with their own need to mature emotionally by belittling. Don’t stand for it.
The find help tab at the top of the page will help you find a therapist in your area and this organization may have some good couple referrals as well.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral