I am so sorry about your health scare. PLEASE take this as a serious warning sign and follow up with your counselor to work on some relaxation techniques. GEL's idea about yoga is great. Try some beginner yoga DVDs or classes.
I oscillate violently between massive guilt over my two illicit R's (whatever you want to call them) and my irrepressible desire for an M that seems so far out of reach. I try to logic myself out of those damaging feelings, but I have just not been very successful.
I guessed you were having those issues. First do you think it is guilt or shame that you are feeling? If it was guilt, then logic might work because you can just tell yourself that you will not do it again. I kind of think you might be feeling shame which is what triggers such an emotional and dramatic response. I do not think that you can easily logic that emotion away. Partly you just have to give yourself a break and move ahead. I think I mentioned before that I believe it will be difficult to show compassion to your wife when you cannot show yourself compassion.
Second your irrepressible desire for a better M. Please do not feel let you have to repress that desire. In fact I would keep that vision of a better marriage as your incentive to stay focused on yourself and getting your life in order. Please believe me that you will feel better and your marriage will improve as you feel better. I think you will probably need marriage counseling to take further steps but I think you will have an easier time convincing your wife when you have taken some initial steps on your own.
Take good care of yourself. You deserve it!!!!
But what is happiness except the simple harmony between a man and the life he leads? ~Albert Camus