I understand you suffer from low self-esteem, it comes from issues of your past....it comes from issues in your current R. What I really hope you realize is this....what you did yesterday took A LOT of courage. You need to recognize what you did and give yourself a pat on the back for being honest....I suspect you don't do that very often.
I'm going to disagree a bit with you on this though "I also need to realize that you don't change from a guilt-driven, low self-esteem person into a "normal" person just because you want to." I believe you do change into this because you want to....but yes, it does take time and effort. It also takes looking at yourself in the mirror everyday and seeing the worthwhile valuable person that you are. You may not see that person everyday, you may not feel like that person everyday....but you need to remind yourself that you are that person, every day.
I'm fairly confident that as you change your W will change too. She's going to take notice of the confident man you will become. She may not trust that change for quite some time, and in all honesty....she may not trust you for quite some time, but time does heal....eventually you two will get back on track. As I said before, if she wanted to be gone...she'd be gone, she's still there. There is still a great deal of hope for the two of you.