Sorry you are in this situation. But at least you found a place that will help you through this. First thing you need to stop doing is snooping. What does it change if he is texting innapropriately with this friend? Would you no longer want to save the M? All you would do is put him on the defensive which will do a number of things. One, he will back off from you even more and to this OW. Two, he will get better at hiding things. What you need to do right now is just take a breath, and start concentrating on you. you say you are working at making some changes...GREAT! Keep working on them. Find things to do to keep yourself occupied or go out and have fun! This is called GAL (Getting a Life). What it will do is show your husband that you can be fine without him and at the same time, will show him the happy side of you...the side that he is attracted to. Don't worry about if he is wearing a wedding ring or not. That is a small thing.
read some of the other situations on this board. You will find several that will be similar. See what others are doing about it. I can't promise you that if you follow the steps in the BD book (or from the advice here) that you will save your marriage. But I can promise you that you will be a better and happier person regardless!
Keep posting in this thread. Try to post your thoughts a couple of times a day. By doing this, you will soon be off of moderation and your posts will appear instantly. Don't be afraid to ask questions to people (in their thread or yours). I will add you to my prayer list.