Perhaps a male perspective would help.
An emotional affair is just as real and as damaging as a physical one, perhaps more so. And, you now have seen both of these issues in your marriage.
Importantly, feelings such as those that you now have do not simply just appear out of the blue. There typically is a very good reason that you would feel (and fear) what you do at this moment, that your husband is still in love with another. In all truth, I doubt you are feeling these things about your husband because you have no reason to. You have been hurt by him, and that hurt is still very much a part of your marriage. And, as you suspect that it is unresolved, this hurt cannot heal. If there is any truth to what you feel right now your relationship cannot grow as another is in between you both. That feeling/person must be removed.
Affairs are beyond painful. They destroy trust, intimacy and honesty between a man and woman. They can be healed, but I have never seen one healed that did not seek out external support, most often professional. There is just too much complexity and pain present, and neither the man or women typically has the perspective needed to get this back on track.
Even if your husband will not go to counseling, I would highly suggest that you do. You need the unbiased perspective and emotional support, and I can tell from this question that you also need to work through what this affair did to you. it seems still very present. The self medicating with food and alcohol speaks to that, and this concerns me.
Although it may seem that he should be the focus as he is the one who had the affair, it is you that needs the ongoing emotional support, as you were the victim in all this and continue to be. Yes; he can change, but you need to be strengthened first, before going after this behavior on his part. Then, when supported and emotionally strong, you have a much better chance of working through what he is doing in your relationship. To do so now, it is too great a risk.
Ask your family doctor for a referral to a couples oriented therapist in your area. You do not need to go together as I mentioned, and best practice indicates that you need support first, before tackling him and his emotional affairs. You can recover from this but need to do so from a position of supported strength via an external counselor. Steven
A therapist will make you aware of what he is doing to you, and how you respond to his behaviors. And, although no person can make another, love.... A good therapist can call a man to responsibility. Love, more than anything else, does not start as an emotion but as a choice and an action. It then turns to feelings.
But, the first step here, without doubt, it to help you feel better about yourself so that you can come at your husband in confidence and strength and without self doubt. For that will make you more able to say and do what is needed to call him to action. For he, not you, is the one who created this problem. He made a choice and now he must make other choices. But a man is more likely to love and stay in love with a confident woman than not...which is why counseling is so key. It also will help you deal with the "what if" pattern that has taken over your thoughts and it will help you stay in the present and fight for your marriage. Steven